It airs at 2 am, eastern - which is 11 pm west coast time. I also believe (though, don't quote me) that it may even be airing at 8pm in Hawai'
And if you need to know how cutting edge Greg is on the technology front---there's this:
And if it's past your bedtime, then simply "tivo" it, a service that allows you to digitally record all of your favorite shows, every time they happen to be on! It's a very interesting device. I am definitely looking into getting one myself.
A very interesting device indeed. Here's a sample to turn your stomach...
UPDATE: Tom Tomorrow has another charming example of "the Gut" laughs.