1. Carrot Top

2. Gallagher

3.  Jerry Lewis

4. Buddy Hackett

5. Roseanne Barr

6. Andrew Dice Clay

7. Dana Carvey

8. That chick with the accordian

9. Milton Berle

10. Billy Crystal

I humbly add:

11. Jackie Mason

12. Pat Cooper

13. Robin Williams

14. Howie Mandel

15. Margaret Cho (Greg W.)  -  I sort of want to like her, and I actually saw her standup live once (I don't remember the exact circumstances that led to that) and thought it was funny, but I have to agree with Greg.  She is usually not just unfunny, she is aggressively unfunny.  And sanctimoniously unfunny.  And self-pityingly unfunny.  Fuck her.

16. Jeff Foxworthy