I once decorated a baby shower using a small washtub (complete with water and lots of bubbles), rubber duckies, baby soap, and washcloths. That turned out well, too, since we used gifts for mom to decorate it.
I made a diaper cake for a baby shower we threw at work. The most amazing part of diaper cakes, for me, is how much stuff is on them. Can you believe I used about 120 size 1 and 2 diapers! It didn't take me more than an hour or two and the couple really appreciated it.
__________________ Virginia is for [knitting] L vers.