Michael Emerson (Ben from Lost) did an educational film for the Federal Bureau of Prisons in 1992.  He comes in at the -12:00 mark.

That was for you, Emily. And for me…

Evangeline Lilly (Kate from Lost) did a phone sex ad:

Brad Pitt did a Pringles commercial:

Paul Rudd did a French Nintendo commercial:

A barely-recognizable Ben Affleck did a Burger King commercial:

So did Sarah Michelle Geller: