On Monday evening’s Dancing With the Stars, we saw our remaining eight contestants do decade-themed dances: Marilu Henner and Derek (the intense team) did a ‘20s-style Charleston; Jana Kramer and Gleb (the hot team) did a ‘70s-themed number set in a Laundromat (why?); Laurie Hernandez and Val (the capable team) did a ‘60s quickstep. But Laurie has never been to high school and doesn’t know what the heck happened in the ‘60s.