Mercenary Merlins

Mercenary Merlins is a rules-light RPG with a free form spell mechanic inspired by Ben Milton's phenomenal Maze Rats. Play with a deck of cards, each containing two words. Mix those words together for a spell name, and then describe it to the GM! Your character sheet is a fill-in-the-blanks dating profile, and spell backfires result in physical mutations to your body. 

Things can get really wacky really quickly. 

(information to make your own cards is included in the main game, but if you wanted a print-and-play solution, you can get the cards for $1 here)

Great for one-shots, but also contains a progression system for longer play.