Hope And Gloria to It's Always Sunny in Philadelphia

Hope and Gloria's title characters visited Friends' Central Perk.

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

Mad About You's Paul did a documentary narrated by The Dick Van Dyke Show's Alan Brady.

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

Alice & Trixie from The Honeymooners crossed over onto Hi Honey, I'm Home!

Here's Lucy's Lucy was driven around Miami by Ralph Cramden of The Hooneymooner's

Here's Lucy's Lucy Carter and Mannix's Mannix are held hostage in an episode of Here's Lucy.

Mannix returned to TV on an episode of Diagnosis Murder to solve an old unsolved case with the help of Dr Mark Sloan.

The airplane that crashed and strand the cast of Lost was Oceanic Airlines Flight 815 also featured on Diagnosis Murder.

Charlie of Lost once dated a girl whose father worked for a paper factory in Slough. The paper factory in Slough is the paper factory of The Office (UK).

David Brent on The Office (UK) wore a Sergio Georgini leather jacket. A Sergio Georgini bag was on It's Always Sunny in Philadelphia.