How Much Art posted:

There was a show that Sam Simon was developing for him and there was a lot of behind the scenes work being done on it, and apparently he ended up just disappearing and never showed up again so they cancelled the show. Sam tried and tried to reach him but couldn't. Supposedly it was related to gambling.

Also I believe they ended up getting Adam Carolla to do the voice of Death on Family Guy because Norm was unreliable and flakey, not showing up for recording sessions and what not. There are TV and podcast appearances he's just not shown up for too... I think I heard things about him not showing up for SNL rehearsals...

I think it was Artie Lange who told a story about how Norm planned to pull a major prank when he was hosting SNL. The plan being, once he was done his monologue (which if you look it up is not very flattering of SNL), he would immediately head to the elevators and leave the building. Apparently he decided not to at the last minute, deciding it would be career suicide, not to mention a dick move.