Super Punch blog has an excellent post running down the top 15 Weirdest Wedding Cake Toppers. I like this one, the steampunk Robot Bride and Groom Wedding Cake Topper, by Etsy seller buildersstudio.
Check out the entire list: Link
Previously on Neatorama: Bride of Chucky Wedding Cake Topper | Another funny one
The two featuring the snowmobile and the ATV are cheesy beyond belief. There is a lady here in my town who makes "custom" wedding cake toppers and they are always just like that - plastic toys sitting beside of the regular topper. Sometimes she throws in one of those bride-dragging-groom figures. I have literally seen them on wedding cakes, in person, three times. She charges fifty bucks each for the things!