The "Kimmel School of Perfect Acting" taught some tried and true (if not completely mental) techniques to the likes of Benedict Cumberbatch, Susan Sarandon, Jennifer Aniston, Lupita Nyong'o, Mila Kunis, Jeff Bridges, Kristen Bell, Eddie Redmayne, and Sean Penn.
Gary Oldman had to try and act his way out of a paper bag, while married couple John Krasinski and Emily Blunt were shown an interesting kissing technique. Unfortunately, it ended pretty poorly.
Of course, Jimmy's enemy, Matt Damon, also played a role in the bit – and it was perhaps his finest acting yet. Hey, it beats getting bumped from Jimmy's show, which is where Matt usually ends up!