IMO 3 year olds are too young for party games. For both my dd's 3rd birthdays I invited about 6 children. I got out lots of toys and they played with those. We then had a party picnic on a rug in the sitting room followed by an action song type CD for the children to sing along and dance.
If you are up to it then sticking and gluing go down quite well and it is also a quiet activity which may help them calm down before going home.