How did Futurama have so many celebrity guest appearances?
I've been going back and watching earlier seasons, which - I thought - had a smaller budget and less recognition. But after taking a closer look at the credits I realized there's a lot of celebrity heads that are voiced by the actual celebrities. The star trek episode actually had the full original cast - and those weren't bit parts! I get that the show's a social commentary, but wouldn't it have been easier to get sound alikes? Is there a story behind the show's giant special appearances list?
by that point Simpsons kind of had everyone who is anyone on to do voicework so i imagine it was just as simple for Futurama
This is answer number 1. The guy from the Simpsons asks you do to voice work, which I have to imagine isn't as much of a pain in the ass as being filmed.
I think answer 1b is they are also getting paid for said work on a show by a legendary creator.
1c is they are usually themselves, which means there's no confusion as to who the person voicing the character is. It's great for their brand.
Not to mention Futurama has its own high profile people that other celebrities would probably enjoy working with, and probably had their own pull.
Also, they originally aired on 20th Century Fox, which seems to have a group of famous people that will pop on to random shows for cameos. I also think it’s easier for celebrities to do cameos as voice overs, since they can be recorded at any studio - even home studios.
Celebrities, oddly enough, typically enjoy attention and the best way to get that is relevance maintained by frequent appearances. Many popular shows (even up-and-coming ones) have cameos from otherwise unrelated actors.
To add to this, famous actors are media consumers themselves. They may choose to go on a show because they're fans of the show and/or the cameo sounds like a fun time. Futurama cameos are particularly fascinating, because they allow actors to play themselves in a very surreal context, and if celebrities have a friend who tells them that the behind-the-scenes atmosphere is a lot of fun, that can be enough.
Just as an example, if you're not aware, Danny DeVito produced, directed, and starred in Matilda pretty much because he wanted to adapt a book his daughters liked.
A fun example is Johnny Depp in Tusk. Dude accepted a nominal fee because he craved the ability to act in goofy, low budget, off-kilter productions again. His agent was mad.
George Clooney and South Park are a good example of this as well.
Also voice work is an easy gig for actors. No need to spend hours in makeup or costume, don't need to wait around for lighting and whatnot. You can just show up, play around with other actors and then go home again.
With 1/6th gravity, you can work and be lazy at the same time. It's like being a voice actor!
Personally I find it really cool that they reanimated Nixon's corpse to make the head's voices.
Mr President, what the hell?
Al Gore made so many appearances because his daughter was on staff as a writer.
Celebrities don't always cost much, you have to remember that those high rates they get paid are optional, there's a base pay for actors, and they can take that rather than their typical high pay if'n they want. Throw in that in a lot of ways voice acting is easier (no costumes, make up, no standing around for a scene to be set up, etc), and it's effectively a quick and easy buck for actors.