As in, "Players may cast spells without paying their mana costs"? Wow. Kinda silly. Mox Lotus at least charged you for that...

I'm not sure, I read it as "whenever a player casts a spell, in the unlikely event it stays in their hand or they can cast it from the stack, they may cast it again for free"... :)

Well, that's what it would actually do worded as it is at the moment, but I don't think that's what V intended... :)

Um, I hate templating, I really do.

Yes, intention was all spells from all players may, optionally, be free.

Luckily, a single added 'may instead' works without changing the effect.

Note: One small difference from mox lotus - that allows an infinite fireball win; this doesn't - though unlike most cast-without-paying it does permit normal sized fireballs. It DOES interact in fun ways with ((FourEcks)) (giving a 16 point fireball for free) and ((May Is Must)) (x spells become 0 spells) however.

Assuming I got my templating right, anyway. I really must put this reasoning in when I first post a card, in future.

If you wanted, you could always just write the card text in normal English and let other people argue about the rules. I didn't mean to be difficult, I assumed you were making a joke with the card :) But "all spells from all players may, optionally, be free" would be perfectly clear, (even though not printable in the rules), because it's not interpreted according the strictures of special magic words.

Nitpick: I assume the wording you're looking for is "Players may cast spells without paying their mana cost" or similar.

(I think the "Whenever a player casts a spell, they may instead cast it without paying the casting cost" means they can cast it for free, but only if they have the mana available to cast it in the first place. Which I assume is not what you intended, but might actually be more interesting.)