By Leah Greenblatt
Updated March 11, 2011 at 05:00 AM EST

Lil Wayne goes Leonardo, Josh Groban goes bananas, and more in the latest clips.

Jennifer Lopez, ”On the Floor”
Pretty standard nightclub stuff, but holy kiss-of-the-spider-woman onesie, does J. Lo look good. B

Sara Bareilles, ”Uncharted”
Like playing Chatroulette — plus celebrities (Josh Groban, Maroon 5), minus unwanted nudity. B

Lil Wayne, ”6 Foot 7 Foot”
Ask not for whom the top spins in this loopy cinematic riff on Inception; it spins for Weezy. B+

R.E.M., ”Uberlin”
Kick-Ass star Aaron Johnson dances like nobody’s watching. (They are.) Inspired and utterly charming. A-