I don't always watch The Colbert Report all the way to the end credits, seeing as my DVR often cuts off the final seconds, so sometimes if the guest bores me, I just delete it and move on with my life. Guess that's how I missed the Colbert/Rain dance-off:

Knowing Colbert's tendency to call out people he knows he can get on the show, it makes me wonder if J.D. Salinger might be making an appearance (though that joke seems to have been a one-off, or at most a two-off)