[Wings of Fire]

Arrested Development, Always Sunny, Louie, Girls, Curb Your Enthusiasm, Sanford and Son, The Cosby Show, Seinfeld, I Love Lucy, The Honeymooners, The Jeffersons, Malcolm in the Middle, Everybody Hates Chris, The Big Bang Theory (don't care for that one)....Shall I go on?

Edit: Didn't notice the twenty year thing, but the majority of those apply.

And dear lord, I'm leaving out so many. Will and Grace, Fresh Prince, Fraser, Cheers, Everybody Loves Raymond, That 70's Show, Scrubs, Roseanne (One of the most important sitcoms of all time), 30 Rock, Community......so on, and so forth.

I'd disagree with a lot of those, but point taken. My definition of sitcom was way too conservative right when I made that post for some reason.