Sometimes celebrity friendships make absolute sense, like Amy Poehler and Tina Fey, united by a shared comedic sensibility, or Ben Affleck and Matt Damon, who have Boston. In other instances, the heavens just smile down in that knowing way of theirs, and lo and behold, we get Snoop Dogg and Martha Stewart’s unbreakable bond. But then there are the cases that belie such easy answers, as if someone stuck pop culture in a Vitamix and called it quits. It’s in that latter mold that we’d slot the rainbow connection between Dave Chappelle and John Mayer (lest we forget, Mayer is not exactly a natural comedian). The duo put their relationship on display on Tuesday, when Chappelle showed up for Mayer’s secret L.A. gig and joined Mayer onstage for some tuneage, including a cover of Nivana’s “Come As You Are†(Chappelle’s a big fan) and Tom Petty’s “Free Fallin’.†See for yourself whether these great (?) tastes taste great together, above and below.