To open 2014, let's look at a live collaboration by the four judges of The Voice. Because it makes complete sense that four musicians working together on a TV show would collaborate at least sometimes! (We are told that Adam Levine is here somewhere, too, but he doesn't seem to be a vocalist on this song)
As part of Gnarls Barkley (along with Danger Mouse), Cee-Lo Green originated this song. However, it's really Blake Shelton and Christina Aguilera that take the lead in this version, recorded live in 2012. And there's no Danger Mouse to be found. Cee-Lo does, at times, show off his guitar skills, which impressed me. Enjoy!