Mrs Columbo to These Friends Of Mine

Columbo spun off Mrs Columbo

Lou Grant centered around Lou as editor of the fictional Los Angeles Tribune which has been featured on Columbo

Lou Grant spun off of The Mary Tyler Moore Show

The Mary Tyler Moore Show's Georgette Baxter crossed over onto Hi Honey, I'm Home!

Sally Rogers from The Dick Van Dyke Show was on Hi Honey, I'm Home!

Richard Diamond, Private Detective's Sam reprise her role on an episode of The Dick Van Dyke Show.

Friends was affected by the blackout created by Mad About You's Jamie on Blackout Thursday.

Caroline in the City's Caroline wished The Single Guy's Jonathan good luck

Fraiser's Niles and Daphne read Caroline in the City's comic strip.

Cheers spun-off Frasier

St Elsewhere's Westphall, Craig and Auschlander visited Cheers' bar

The Bob Newhart Show's Elliot Carlin visited the psych ward at St Elsewhere's St Eligius Hospital.

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

Ellen and Grace Under Fire crossed over in a cross over themed night

These Friends of Mine was reworked to create Ellen.