I've been watching some old clips of him on Letterman...some of his jokes from his "books" were hilarious.
Guy walks into a bar with his dog.
Bartender says... Go over to Sam's if you want to put a dog on the stool.
Guy says, but this is a talking dog.
Guy says, I'll have a vodka tonic and dog says I'll have a light beer.
Bartender says, Take your ventriloquist act out of here.
Guy says, I'll go and lock myself in the bathroom and you ask my dog what he wants to drink.
Bartender asks, What do you want to drink?
Dog says, I told you. I want a light beer.
The astounded bartender says, Here's 10 dollars... Go over to Sam's order a light beer, spit it in his face and tell him my beer is better than his!
Guy returns and asks, Where's my dog?
Bartender says, I sent him over to do a pratical joke over at Sam's.
Guy says, I really wish you hadn't done that.
Guy goes out of the bar and sees Rover banging a dog in the middle of the street.
Guy says, Rover! What are you doing? I've NEVER seen you do such things before!
Rover says, I've never had 10 dollars, before.