One that I have seen is you partially melt chocolate bars and smear them in some diapers. Everyone has to guess which candy bar it is based on sight, smell, taste, feel, whatever they wanna do. I can only imagine seeing all of these grown adults putting their faces in "poopy" diapers. :D
I have a list of games in my journals
At my cousins she had a co ed baby shower and her and my aunt froze little itty bitty plastic babies in ice cubes and gave them to everyone (including guys) and whoever melted the ice the fastest using only your body had to yell "My water broke!" Some guy melted the ice and had the little plastic baby first. It was really funny. Everyone enjoyed that one lol
At mine we played a few one was putting a diaper on a doll blind folded, whoever did it the quickest won a prize. Another was everyone partnered up and wore blindfolds and one had to feed the other apple sauce, note it was hilarious.