One Degree: Robert Downey Jr. and SNL

My faith in One Degree is restored. Two weeks ago I decided I would go on hiatus until I thought of topical One Degree trivia starring well-known actors who were in or about to be in the news, which would rule out actors like Romola Garai and Benedict Cumberbatch. However, two people correctly wrote that those two British actors had starred in Atonement and Amazing Grace and it wasn't even a formal question. So now I know a few people are paying attention.

If there is one actor who is in the news this week, it's Robert Downey, Jr. and for once, it's not for getting arrested. I've been overdosing on Robert Downey Jr. trivia following the release of Iron Man so now my entire left hemisphere is flooded with factoids about RDJ. In fact, my brain's so full, this may just kick off the start of Iron Month, just so I can purge before I go into shock. Here's the challenge for week one:

Robert Downey Jr. was a cast member of Saturday Night Live for one season and has starred with at least three other actors who once starred on SNL--name the cast members and the movies they appeared in together (Bonus points for identifying his favorite SNL cast member).

Answers next week! Post your answers to the comments! I made this one up, so maybe there's even a fourth cast member he's starred with--show me up! We will add your biological and technological distinctiveness to our own...