http://www.ababyshower.com/mywabrbbashg.html
This was a lot of fun. Instead of having everyone suck or bite on their ice cube, I put them each in a cup. While we were eating everyone was watching their baby to see whose "water would break" first. (aka, whose ice cube would melt first).
I've seen the candy bar in the diaper game like the pp said.
At my shower they filled up a giant bottle (piggy bank) with a bunch of little baby items. My mom walked around with it and then took it away. Everyone had to write down as many things as they could remember. It was okay, but not the most fun!
Also at my shower, every guest was given a little cloth diaper cutout and a pin to pin it onto their shirt. After presents were opened my Mom told everyone to "change their diaper" meaning to open it up. 2-3 of them had a yellow/brown mark that she had made with a marker in it to symbolize pee or poop. Those were the winners. I think she bought that game at a party store or somewhere, but you can cut out your own diapers using cloth.
Have fun!