Jimmy Fallon Sings a “Mario Kart Love Song” with Selena Gomez. Because Why Not?

Jimmy Fallon's been about as high-profile a video game enthusiast as you can get these last few years. His late night talk show has offered up early looks at big releases like Halo 4 and the Wii U, along with offering exposure to developers and execs. But this new singalong with Disney starlet Selena Gomez is…