I just threw my 6 year old a Lego party. It turned out great. We played two building Lego games. One was build the highest tower and the other the most creative. I was able to purchase Lego toys for prizes at very discounted prices after the holidays.  (I got Lego Knights for only $2.48) We played put the Bionicle mask in the middle game.  (Like pin the tail on the donkey) I also played hot Legos (like hot potato)  I filled a plastic container with legos, we played music and the kid with the container when the music stopped got to do the music.  (It made being out fun) We had an estimation jar which the kids got to keep what was in the container. I played Lego bean bag toss, bowling and I spray painted boxes that they could build with (I took cereal boxes, granola bars, etc. and spray painted them)  My Lego cake was a sugar cookie (my son didn't want a cake) I put the cake in a rectangular cookie sheet and baked it. I got round cookie cutters for the circles and took frosting tubes and wrote Lego on those. I also made extra chocolate chip cookies that I made into squares and we let the kids decorate them. The day after the party my sons friends kept telling us how much fun they had.  A 2 1/2 hour party was the perfect amount of time.  I hope this will also help another family give their child a really memorable party.