Gender reveal party. I still like a cake for the actual reveal. And having the ultrasound tech write boy or girl in a sealed envelope for the baker, so no one at the party knows what it is until the reveal.
There are lots of creative ideas and ways in which the gender can be revealed. Many of the ideas involve baked goods with pink and clue colored filling, but I think that if you're going to take the time to throw a gender revel party, the gender reveal idea should POP!