Donna Summer's death has us feeling verrrry nostalgic -- we share memories of the Disco Queen with Ms. "I Will Survive", Gloria Gaynor ... and "Dance Fever" host Deney Terrio. What's Donna's best hit? The pick is unanimous ... almost. Plus, UFC badass Chael Sonnen drops by to prove he's more than a hitting machine -- politician, author, Anderson Silva hater, vegan hater, and admirer of Charles' dreads? You gotta see this guy. And the Situation breaks "Jersey Shore" news ... under oath!