Here are five sites that are funny hell and must see at least:
http://www.newgrounds.com
http://www.joecartoons.com
http://www.jibjab.com (I recommend 'Capital Ill' and/or "Mutha Fo Fathers")
http://www.campchaos.com
http://www.lanet.lv/users/judrups/Humor/aol.html -For those who are not AOHELL might find this funny, though it is not flash (bear with me, I thought I had five, so I was gripping for another site).