Sometimes you don't even need to mess with the shape or flavor of your wedding cake to make it stand out. All you really need to do is switch out those boring old bride and groom cake toppers with something cooler, more unique and undeniably you.
If you're going for pure shock value, get a traditional cake and top it with something extremely unconventional, like large plastic dinosaurs or toy aliens. If you're trying to keep it classy, use symbols that are important to you both. Anything from religious iconography to little plastic peace signs will work. If you want to thumb your nose -- and cake -- at contemporary expectations, go for traditional bride and groom toppers in unconventional poses. You can find them doing anything from playing baseball to engaging in a passionate (and somewhat explicit) kiss.