Everybody loves a simple game made overly-complicated!
Here's my version of Rock, Paper, Scissors, in a set that can be played by two or three players.
It's a quick play, ideal for a coffee break in the office (printed on office supplies, of course), in a quiet time in your school lunch break or between bands at a festival.
I have added the files in PDF versions, but also in DXF format, in case you fancy making a set with a laser cutter...
UPDATE: November 2014:
If you are playing the two-person version with younger players, the game runs more quickly and generally "better" if, when a piece is taken, both pieces are removed from play. thanks to wbaca for working that one out.
This is why instructables have comment sections!