Update 2: Teri Hatcher explains how Conan hurt his head.
Update: according to Variety, it is expected that Conan will be back on Monday night.
NBC issued a statement (through Aaron Bleyaert) that The Tonight Show would be a repeat tonight with the following message:
Hey guys! Change of plans tonight. Here's a statement from the network:
Tonight, NBC will broadcast a repeat of "The Tonight Show with Conan O'Brien." Conan hit his head doing a stunt and the show was not finished.
Conan O'Brien added, "Last thing I remember I was enjoying the play with Mrs. Lincoln, and the next thing I knew I was in bed being served cookies and juice."
I'll post more details as they become available!
I have no doubt that for this too, Jay Leno will be blamed! Kidding aside, I hope Conan is fine. Despite the levity in Conan's statement, it's hard to get a read on what happened or how serious it is.