1. George Harrison - The Simpsons

Back when "celebrity tv cameos" usually meant special episodes where a celebrity would walk out and get huge studio-audience applause and then perform one of their songs or say their catchphrase, The Simpsons inverted the form by bringing in George Harrison then having him utter two sentences while Homer devours brownies in front of him.

Looking back on his time with his band The Be Sharps, Homer reminisces, Then came the greatest thrill of my life...

Harrison shows up for one more line at the end of the episode to rip on Homer's group re-uniting on a rooftop.

2. Hugh Jackman - X-Men: First Class

X-Men: First Class was a near-total-reboot of the X-Men franchise complete with a mostly all-new, younger cast, but the creators still reached out to Hugh Jackman about reprising his role of Wolverine, which he did, for exactly one ad-libbed sentence that earned the film its PG-13 rating:

3. Robert De Niro - Extras

Extras took the very concept of celebrity cameos to another level of craziness, but nothing was more elaborate than this cameo; after establishing for two seasons that Ricky Gervais' Andy Millman character got into acting because he idolized Robert De Niro, Stephen Merchant's hopeless agent character promises to set up a meeting with him, but Andy doesn't believe him and skips out.

So, the show literally booked Robert De Niro to just sit there and play with a novelty pen:

4. Bob Saget - Half Baked

Bob Saget appeared in Half Baked to deliver one line at a support group for drug addicts, a line which we would later come to regret when, he claimed, people on the street constantly shouted the line at him when he in public with his children:

5. Robert Patrick - Wayne's World

Robert Patrick, aka The T-1000 from Terminator 2, makes one of the most out-of-the-blue cameos imaginable when Wayne's World breaks the movie-universe-4th-wall for an extremely weird one-off joke:

6. Lauren Bacall - The Sopranos

In Sopranos Season 6, Christopher flies to Hollywood to approach Ben Kingsley about being in his movie, but after failing to win him over, Christopher panics and ends up mugging Hollywood legend Lauren Bacall so he doesn't go back east empty-handed. On a show of wonderfully surreal moments, the fact that actual Lauren Bacall agreed to this is just really amazing:

7. Jonathan Frakes - Futurama

Futurama reunited almost the entire cast of the original Star Trek for the episode "Where No Fan Has Gone Before," but also snagged Jonathan Frakes, aka Commander Riker from Next Generation, just to say one line: