Some Relay for Life theme ideas are: Olympics, farmstead, western, holiday, winter and Woodstock. Relay for Life can also have a movie or book theme where participants can dress up as their favorite characters.
An Olympic theme is a classic Relay for Life theme. Build a track similar to those used in the Olympics for the runners to use. Decorate the area with a podium, and give out gold medals to participants. A torchbearer lighting the Olympic flame starts the ceremony. Dress up participants in track outfits with names of their sponsors instead of countries; wear togas before and after the relay laps.
For a farmstead theme, place fake animals, hay bales, tractors and barn cut outs to give the illusion of being on a farm. Dress up tents like small barns with bales of hay nearby. Give hayrides in the tractor for all the guests and participants.
Dress up as cowboys for a western themed relay. Decorate the rest area like an old fashioned saloon, and give out sheriff stars for all participants to pin onto their clothing.
Book or movie themed relay can transport people to another world. Dress up Participants and volunteers as favorite characters from a movie or book chosen in advance. Decorate the relay area to look like a scene out of the book or movie, and have the characters run through. Replace the relay with an item from the book or movie, like a wand from Harry Potter.