We had ours at play group so there was heaps for them to do, so didn't bother with games.
Went to two in the weekend - one had lots of stuff set up out side eg sand pit, tents, bikes, chalk, water play etc and the kids all had fun.
We played pass the parcel at the next one and it all went well - most of the kids hadn't played before, but before the end most of them had worked out to hold on to the present for ages before passing it in case the music stopped
Enjoy the party and happy birthday to your DS!
ETA - one we went to a couple pf weeks ago did a treasure hunt in the garden with little bottles of bubbles as prizes - most of the kids needed adult help to find the presents, but then they all played with the bubbles.
Edited by DJ