Multiclass: The RPG System!

Multiclass: The RPG System! is a very, very simple classless system for fantasy role-playing. If you want, you can have a sword-slinging thief that can cast a spell or two and heal, and it actually doesn't break the game at all, because it's designed for exactly that! (You might not think it'd work probably, but in playtesting, it has actually seemed to work just fine!) When you've only got a GM and 1, 2, or 3 players, Multiclass: The RPG System! can also be handy for helping players fill in the "party role gaps" that a module your GM is converting over from some other system might have...