You can use movie/tv "drops" in station elements; promos, liners, etc. But you CANNOT use that copyrighted material in commercials.
It's ok to use them to sell your station, but it's not legal, ie copyright infringement, to use that same audio in a commercial for a client. Why? the client is deriving revenue off the usage of said copyrighted material, ie, the client doesn't own Harrison Ford's, or Homer's voice. Can't receive revenue via devices or images one doesn't own. Hence when someone uses Jennifer Lopez's likeness to sell a product, and they haven't paid her for the usage of her likeness, copyright infringement.
Same goes for music. Can't use a song...not even 5 seconds, for a client that hasn't paid for it's usage. Client must show proof that they've received permission.
I have a meeting every quarter with Sales, and when new staffers are hired, to go over copyright infringement, so that they understand it and can then pass it onto a client. I hate it when a vet, in this mid size market, will say "we've always done it this way" or "this client has always used the MNF theme for thier spots". I reply..well, you were breaking the law and putting the cluster, it's management, your client and this company at legal risk. They shut up quick!
And regarding using Simpsons (sooo old!) or Southpark, or some other overused drop in imaging - lame and tired. It's been going on like that since the '70s. Use audio from sources that aren't recognizable - burn factor is lower. Or as said below, use a drop in a way that it hasn't been used, ie "get down" from Han Solo for a disco promo.
Using real people, off the street audio, for liners instead of the VO guy is also a way to keep the produced VO stuff from burning.
Writing is key. John Frost, Joel Moss (WEBN), Eric Chase, all great writers. Like a movie or tv script, if the writing's not there even Pacino can't polish that turd. It all starts with good writing. The writing will dictate how it will be produced.
I'm sure the VO talents that frequent this board can attest to the crap they've had to read. And/or if they've ever worked at a station doing production, the crap a PD may have written.
Jeff Laurence was my VO at WTRG/Raleigh...hopefully my stuff wasn't crap?!!
I can't stand it when producers will write something, or a PD, and then toss in a drop that has nothing to do with what was/is being said.
If you have drops in mind for a project, WRITE AROUND THE DROP. Joel Moss is great at that. Moss is the granddaddy of rock imaging. He's been at it, at WEBN alone, since 1984. Pure theater.