Real-estate dilettantes Clipse were the guests on Jimmy Fallon last night, where they did their awesome single “Popular Demand” backed by the Roots (sans Cam’ron, but with a verse from Black Thought). Even better, the two groups got together on throwback jam “Grindin’” for this web-exclusive video. And even better than that, Questlove recorded the (bright-and-early) practice session for “Grindin’” and then tweeted it. A few thoughts: First, how funny is it that the Roots’ practice space is the size of a compact sedan? Second, it makes us feel a little better about our limited skill set to know the Roots aren’t totally insanely virtuosic session players and actually have to practice before playing backup band to every musical artist in the universe. Lastly, and this has been pointed out elsewhere, but Fallon’s really bringing it with the musical guests, huh? Jimmy for 11:30!