Make a corsage of silk roses, put in a paper bag, a large grocery bag is just right; roll the top of bag down a couple times, so it won't come open, staple shut. Tell guests there's a pair of old time bloomers in the bag and whoever is left holding the bag when the music stops has to put them on and and let everyone see how they fit. When you finish laughing give the corsage to the honoree. Just play music long enough to pass the bag around 2 or 3 times.
Also have a small notebook, wirebound, ask each person to write their favorite tip for baby on a page and any other notes they would like to share with the new mother. You can decorate the front of the book in like manner suitable for mother to enjoy reading.
Cut white paper in triangles, enough for everyone to get at least one, perhaps 2 of them. In one of them mark with brown marker. Fold as a diaper, pull over each side to the middle(on the long side) then fold the bottom up, it will look like an old fashioned diaper then pin with a gold safety pin in the middle. Who ever gets the poopy diaper wins a prize. All the prizes should be baby themed so they can be given to expectant mother.
Hope this works out for you and you have a great shower.
delma