I've found some of these funny clips from a friend that had a rather large collection. I've been thinking of adding more clips but it's hard to tell if they'll be funny enough.
Many of the places these clips came from are the same places that show up here in the referral list. These sites have some really funny videos or 'funnyclips' as I call these gems. Unless the site is obviously a search engine I recommend trying it out. Heck, even if it's a search engine it's probably a link that'll take to you a search for some funny stuff.
