remember Fallingman? I wish he'd come back. anyway, make a card that lets you cast one or more spells from your hand without paying their mana costs. emphasis on "from your hand".

you have until this time Friday. go!

Mind Tempest
Sorcery (R)
Draw X cards, then cast a spell from your hand with a mana value of X or less without paying its mana cost.

Peer Review
Sorcery
Will of the Council - Reveal your hand. Each player votes for a nonland card revealed this way. You cast each spell with the most votes or tied for the most votes.
"I don't know what's crazier: that the Grand Council of Critics finally agree on something, or that they all agree my show is terrible!"

Unlock the Secret

Enchantment (M)
When Unlock the Secret enters the battlefield, investigate three times.
At the beginning of your upkeep, if you control no Clues, exile Unlock the Secret. When you do, you may cast a card from your hand without paying its mana cost.

Cosmic Epiphany —
Instant (R)
You may cast a spell from your hand without paying its mana cost.
“When you look into infinity, you realize that there are more important things than what people do all day.”
—Calvin, to Hobbes

Research Grant

Enchantment - Aura
Enchant Creature
Enchanted Creature has Prowess and "Whenever this creature deals combat damage to a player, you may cast up to one instant or sorcery spell with mana value less than or equal to the damage dealt from your hand without paying its mana cost."
There is no sweeter moment for a Tolarian scholar than receiving a grant and none more terrible than explaining how they spent it.

Trainer of Squires
Creature - Human Knight (R)
First strike, vigilance
When Trainer of Squires enters the battlefield, until end of turn, you may cast a Soldier spell with mana value 3 or less from your hand without paying its mana cost. A spell cast this way enters the battlefield with your choice of a first strike or vigilance counter on it.
3/3

The Black Oath |
Sorcery

Destroy all nonlegendary creatures. You may cast a legendary black creature or planeswalker spell with a mana value of X or less from your hand without paying its mana cost, where X is the number of creatures destroyed this way.

Ob Nixilis wished for a world without war. The demon smiled.

Spell Salvo

Instant
You may cast up to three red instant or sorcery cards from your hand with mana value 1 without paying their mana costs.

Evelia, Melodic Temptress -
Legendary Creature - Demon Wizard
The first spell each player casts on their turn has cascade.
Whenever an opponent casts a spell without paying its mana cost, draw a card. Then, you may cast a spell from your hand without paying its mana cost.
3/5

Should be okay in EDH I guess?

I can't think of a submission but I just wanted to say that Zephyranth is cool as hell

nvm

Synchronomancer
Creature - Human Wizard
Whenever you cast a spell from your hand, you may reveal a card from your hand that shares a name with that spell, and cast it without paying its mana cost.
2/2

(in case it's not clear, if you have 3 or more cards in your hand with the same name, this process can be repeated)

closed!

I don't know if mind spring is weak enough that this level of upgrade is fair. there's been some mild strictly-betters, most recently silver scrutiny, but this is a lot of potential extra value. beyond that, though, I think it's cute. reminiscent of things like epic experiment. I think I'd like it more if you added a third color to the cost. maybe green? dunno, just feels like it'd benefit from being a tricolor card thematically, and would also help balance it a bit more.
3/5

I'm ok with multiplayer-focused cards, but I think they should still work in single player, and this doesn't. I can just choose whatever I want, and it's guaranteed to at least be tied. maaaybe if it only let opponents vote? that feels in line with the flavor, but still a lot of potential value if you just build a deck that's just this and broken expensive things and then mulligan into this. a little fragile as a combo deck 'cause you can't run protection, although you can do proactive stuff like thoughtseize as long as you make sure to play those first. maybe each spell that received two or more votes? that's unlikely to do anything most of the time, though. but anyway I can't grade this fairly against the other submissions without considering its behavior in two-player formats, and in those formats it just can't work.
1/5

this feels strong but actually demands you invest 10 mana before you get the return, so it's the tantalizing kind of strong where it's unlikely to just take over a game. not entirely sure what three clues is worth on its own, confirm suspicions is the only card that does it and that has the counterspell thing as well. clues are worth less than cards, though, so concentrate is probably a good barometer, and with the extra rider I think this is about right. would've loved some flavor text but I think it works well without it.
5/5

it works, but it doesn't really feel interesting. especially since maelstrom angel already did the "five-color spell lets you cast things for free" angle, I'm not really sure what this is adding. I could see it printed as-is if they had some reason to want something like it, sort of a gold dramatic entrance with more flexibility, but unfortunately it doesn't do anything exciting. I do like the flavor, though.
2/5

prowess and a damage-based spellcasting trigger feel a little awkward together, but I suppose they both work in the same sort of deck even if they don't work with each other. the flavor's really good, and the card opens up some cool play options. echoes of the prompt card, but not overly so. I wonder if this'd work better as a creature, since it's a little weak as an aura, but I think it works well enough.
3/5

beyond the criteria, I'm not sure why this doesn't just put the soldier into play. I guess shields of velis vel exists, but if you're worried about that you can just say "Soldier creature". you're having to twist the wording around in order to fit it into a spell-casting mode when really it just wants to let you put the creature down and add a counter. I do like the card quite a bit, and having it give your choice of the two keywords the actual knight has is very cute. would just be a better card if it weren't made for this criteria, which is unfortunate.
3/5

similar to Otu, I'm not sure why this doesn't just put the card into play. admittedly it doesn't cause wording issues on this one, but still, functionally equivalent. the main point of casting cards without paying their mana cost is to either include non-permanents or to open up timing, and this does neither. beyond that I like it a lot, though. the flavor's really strong, and the card is clever.
4/5

huh. reminiscent of fires of invention, but definitely its own thing. potentially a lot of value, but very hard to use. probably needs playtesting to find the right cost, but 3 seems like it might actually be right: low enough to be tantalizing but harder to get a lot of value from than it looks. really interesting, would love to see it in real Magic. flavor's great, too.
5/5

pew pew pew! fun. trying to imagine a combo deck that can chain these together, since it can cast more copies of itself. magmatic insight would be critical. fossil find to get back the salvos. needle drops for value. there's no way it'd work but I like card that get me thinking like that. would've liked some flavor text, but mechanically very cool.
5/5

I had to look it up to double check, but cascade does let them choose not to cast the card once they've found it, which makes this much more reasonable. the card draw makes it basically never right for them to cast the card unless they're completely desperate, though, making it a bit close to maelstrom nexus. maybe without the draw it might be plausible. even then it's pretty strong, although I just realized the first ability only affects cards players play on their own turn, so the free spell she gives you won't also cascade, which makes it a lot less scary than I thought it was. I dunno. I'm waffling between loving this card and just liking it.
4/5

I feel like the original wording of this worked just fine? not sure why you switched to the reveal-based wording. still, though, I like the design a lot. could maybe have a slightly bigger body, since it's unlikely the condition will come up all that often without a lot of work so it might as well also be a playable creature on its own, but the ability is a neat twist and seems fun to try to build around. could use flavor text, but mechanically very interesting.
4/5

three 5/5s, but only one of them had flavor text, so I'm giving the win to Jo! congrats, nominating now, see you tomorrow.

I was treading between this version and the 'cast or draw' version but my thought to capitalize on EDH's singleton desperation won out in the end (Since unless shuffle, good chance whatever they cascade into will never see play if they don't cast it.). On hindsight, I actually wanted to make the body smaller for easier removal or 1 cmc higher since her ability is asymmetrical in a sense as there isn't any downside to your own cscade.

I had the extra green in the cost right up to right before I posted it. Really though, I just find it to be a bit bland and wish I had posted something better. Oh well, next time!

I convinced myself that the original wording was clunkier than the final one, but now that you mention it I am pretty sure that the reverse is true. and yeah it could definitely have used flavour text but I've always been terrible at writing it, so I tend to just leave it off and hope that you don't comment on it