The title isn't exactly what you were thinking this post was about. :-) Derek has recently been playing with his trucks in our bathtub. My initial reaction was "the tub, really?" but the more I thought about it the more it makes sense.
1) His trucks fit nicely around the edge of the tub for a nice "race track".
2) For the most part, Brooke can't reach his trucks or destroy his track.
(If you look closely you can see Mater in the "pit stop" and a few trucks working "in the hole")