Hi J.,
You could try some tried and true games like:
*Clothespin drop (kids stand over an empty jar, touch clothespin to tip of nose, let it go and try to get it to fall in the jar)
*Make your own pin the tail on the donkey
*Scavenger hunt
*Bean bag toss (make your own bean bags - if you don't sew, it can be plastic snack size baggies - and toss through a hula hoop or a piece of cardboard. If you use the baggies, double bag them and tape them closed)
*Ping pong ball toss (into a bucket, they are super bouncy)
*"Who Am I" Guessing game (tape a piece of tape on each child's back and secretly write the name of a famous person on the back - the other kids can give them clues as to who that person is without revealing the actual name - the kids have to guess who they think they "are")
*Word scramble or crossword (perhaps with birthday-themed words including the birthday child's name)
Kids also love a "do-it-yourself" food bar, like make your own tacos or ice cream sundae.
Hope this helps. Have fun!
M.