Luke loves to lay on his back in the bathtub (I have pictures of this that I'll post later), and he's figured out how to make really big splashes by lifting up and "dropping" his feet into the water. Virtually as soon as we put him into the tub, he flips onto his back and starts splashing. We've dubbed whichever direction his feet are pointed the "splash zone" as you're definitley going to get soaked if you're in the area.
(Please note my strategically placed modesty washcloth. ha!)