Do a co-ed baby shower, and host a poker game for the guys. Entry cost or ante, is one full size package of diapers. The guys prize,they get to play poker and be around other guys!
Games, guess the baby food, get five or six jars of baby food cover the label and have your guests guess what flavor it is.
baby item scramble...scramble the names of popular baby items, the person who gets the most wins!
cost is for the paper...if you have a printer at home...
Simple prizes: my friend had shower gels and lotions for prizes.
Couple of ideas...