Jimmy Fallon and Justin Timberlake, duh. I can't get over the combo-- they're just crazy hilarious. I'm not even a big fan of JT, but him with Jimmy is just something truly wonderful. Below is The Ragtime Gals version of "SexyBack," The History of Rap (only parts 2 and 3, but still crazy awesome), JT's impression of Jimmy, and the Barry Gibb Talk Show skit from SNL. Enjoy. You're welcome.
(wish this was better quality, but it was the best I could find)