Everybody Loves Raymond to Joanie Loves Chachi

The Nanny's Fran Fine and Everybody Loves Raymond's Raymond Barone went to high school together

High Society and The Nanny crossovered during a network crossover theme night

High Society and Murphy Brown crossed over during a network crossover night

The Bob Newhart Show's Carol was Murphy Brown's secretary for an episode.

The Bob Newhart Show's Bob Hartley woke up after dreaming the entire series Newhart during Newhart's finale.

Newhart's Larry, Darryl and Darryl squatted in Coach's Hayden and Christine's home

On a network crossover night, The Drew Carey Show, Grace Under Fire's Grace Kelly, Coach's Luther and Ellen's Paige and Spence all show up. Finally on Ellen, Paige and Spence run into Grace Kelly and Drew Carey

The Drew Carey Show's Mimi appeared in an episode of The Hughleys

The Hughleys crossed over with The Parkers.

The Parkers was a spinoff of Moesha

Hakeem and Niecy from Moesha went to the prom with Cher and Sean from Clueless.

Sabrina from Sabrina the Teenage Witch visited Cher from Clueless in the episode "Mr. Wright."

Sabrina the Teenage Witch also crossed over with Boy Meets World on several other occasions.

Boy Meets World and Step by Step both had episodes at Disney World and whiel in Disney World Eric from Boy Meets World met Dana from Step by Step.

The family from Step by Step was in the middle of a barbeque outside when Urkel from Family Matters came (literally) crashing in on the jetpack he had built on the last episode of Family Matters.

Family Matters was a spin-off of the character of Hariette and Carl Winslow from Perfect Strangers

Perfect Strangers' featured a game show segment in which the toilet was provided courtesy of Cunningham Hardware in Milwalkee, WI, owned by Howard Cunningham of Happy Days.

Joanie Loves Chachi was a spin-off featuring Happy Days