AisleDash

A simple and practical shower theme is the recipe shower. Each guest is sent a recipe card in with their invitation. (If you like the ones in the picture, you can find them and more at Pink Bathtub on Etsy.) The guests fill the card out with a favorite recipe, and when they arrive they share the story of that particular dish: why they like it, why they think it suits the bridal couple, who gave it to them ... any little tidbit that will make its special significance clear.
The people at Apartment Therapy suggest that sharing these stories can replace the need for wedding shower games, but if you really like shower games, there are all manner of food-related activities that could go along with this idea.

Here's one: put a pinch of a different spice in each of several small plastic bags. Hand each bag around the circle, along with a felt pen, and have each guest write their name and what they think it is on the outside of the bag. The person who gets the most correct answers wins!