Apart from the titles already posted, u can try the following flims which i found hilarious but might not measure up to the "clean quotient".
1. A Fish Called Wanda [This one had me in splits]
2. Cactus Flower [This is a brilliant classic]
3. The Odd Couple [This too is a classic]
4. The Airheads [This is a laugh-aloud for rock 'n roll freaks]
5. Fun with Dick & Jane
6. Cheaper By The Dozen 1+2
7. Mr Deeds
8. Duplex
9. The Scary Movie series [they are basically spoofs of very well-known flims & are fun in parts]
10. The Perfect Catch
11.Tootsie [This one is a must-see, Dustin Hoffman is UNBELIEVABLE]
12. Big Momma's House 1+2
13. Miss Congeniality 1+2
14. My Best Friends Wedding
15. Legally Blonde 1+2
16. Shallow Hall
17. Ice Age 1+2 [Highly recommended]
18. Madagascar
19. Antz
20. Anger Management
21. Her Alibi
22. Three Men & a Baby [21&22 are Tom Selleck classics]
23. School Of Rock [You Must watch this, Jack Black is simply mind-blowing]
24. Shark Tale
25. Charlie & the Chocolate Factory [You'll love it]
26. Coming to America
27. Daddy Day Care
28. Me, Myself & Irene
29. Ace Ventura 1+2
30. One flew over the Cuckoo's nest [This is a heart-wrenching, critically acclaimed film, with some exquisitely exihilarating moments].
Finally for wholesome, clean fun don't forget to check out the
"Home Alone" & "The Pink Panther" series & specially "Baby's Day Out".Try the latest Pink Panther film starring Steve Martin but don't give the original ones starring Peter Sellers a miss.