Anyone interested in doing their first adventure race should check out Infiterra's Summer Quest race. It's a short 4 hour race that combines running/hiking, biking, paddling, and orienteering. It's only $45 and the paddling is optional so you don't have to do it if you don't want to spend the extra coin on a rental. The Infiterra crew puts on a nice race so you won't be disappointed.
More info can be found HERE