So I found this little gem of a game called Zwok. Basically, it's a snowball fight, but online! It's actually quite a fun little game. Catchy low-key music, great art, and easy to pick up! You can either join up and create an account (and save your scores, stats, etc) or just play anonymously. I'm "halation" on the green team if you ever see me.

The gameplay is also very basic. Use the arrows to move your player, then click the mouse to aim. After everyone's made their choices, the server updates and you get to see who hit who. Last team standig wins! This game was apparently created by Sony Computer Entertainment Europe.