What are some good theme ideas for a baby shower?

Baby shower themes are typically based on the type of presents that the mom needs. So, unless the baby shower is a surprise, it is a very good idea to consult the mom to find out what she needs most. From there, you can determine the theme of the baby shower.

Some unique themes that fit well with this type of planning include:
Times of day: Guests are asked to bring gifts that correlate to a baby's day, i.e. bath time, nap time, feeding time, etc. Make sure to designate to guests which time of day they are buying for. You can also coordinate the gift-opening by moving through a mock day for baby.
Nursery: Guests are asked to bring things to deck out the baby's nursery—everything from diaper pails to linens to mobiles and more.
Basket shower: Guests are asked to bring a basket of goodies for mom filled with different items; examples include a bath basket, diapering basket, book basket, and toy basket. For this shower, make sure to designate to each guest the type of basket to create so there will not be duplicates.

One additional idea that I particularly like is to ask guests not to bring mom a card with their gift, but rather to bring a small book to begin baby's new library! It's a bit of a twist, and moms love it!