Heroes have to do something in their spare time, so why not roller derby? Turns out the heroines of both Marvel and DC love to get their skate on, and thanks to artist Kevin Bolk, look completely adorable doing it. His art has always been incredibly fun and colorful, and his newest set is no different. You can catch the rest of the set of 16 art cards in the gallery below, and you can find more of his fantastic art on his Deviant Art page. Just for kicks, who do you think would win in this epic standoff? My guess is between Black Widow and Mystique, all of DC's team would have skates on bricks or exploding helmets, but hey, all is fair in war and derby.