Margarine vs. butter: one of history's hottest rivalries? (Photo: Flickr)

We kick-off the third season of Tell Me Something I Don’t Know with a show on competition of all kinds: athletic, sexual, geopolitical, and the little-known battle between butter and margarine that landed in the Supreme Court. Our panelists are:

Steve Levitt, my Freakonomics friend and co-author, who didn’t quite fit-in with sports teams.

Bridget Gainer, Cook County commissioner, who took a sibling rivalry well into college.

Scott Turow, lawyer and author of Testimony, who faced-down another best-selling author in the courtroom.

Our real-time fact-checker is WBEZ’s Tricia Bobeda, co-host of the Nerdette podcast.