What are some good crafts for a kid's birthday party?  

Well first, it all depends on the ages of the kids. Kids of different ages love doing something different. Maybe having a few tables set up where they can spend so much time on one craft and then keep moving to the next until every craft is finished.

Get some lolly sticks, feathers, felt, googly eyes ect and see who can make the strangest monster. We did that at a party once, kids loved it.

are they girls or boys? what about buying some picture frames and decorating them with foamie bits, stickers, beads (just about anything). beading is always good but what about making a key chain or zipper pull with beads? or you could make God's eyes (here is the link) http://crafts.kaboose.com/gods-eyes.html