I'd never heard of a diaper raffle before, but this was a cute idea. Guests were asked to bring a package of diapers for a chance to be entered in the diaper raffle. My friend has a Cricut scrapbooking machine and made adorable onesie raffle tickets.
Also, instead of cake, we had Holy Cow cupcakes (Carmel, IN). These were absolutely fabulous! We also had little onesie confetti on table (again, courtesy of my very creative friend!)
However, if you are feeling especially creative and have an afternoon to spend in the kitchen, I would recommend the belly cake! I used the Wilton ball pan and two large cupcakes for this masterpiece.