Halloween Themes

A few times friends have had themed Halloween parties, where your costume had to somehow match the theme.

What are some good party theme ideas you've either participated in, or even just thought of?

Dead Celebrities: This can be fun but does tend towards bad taste. Don't be surprised to get multiple Elvises! My fave was in pretty bad taste, a guy had a toy helicopter imbedded in his head and went as Vic Morrow!

Undead: What's great about this theme is you just can't have TOO many zombies, LOL!

Monster Mash: Again, plenty of variety here.

Sci Fi and Aliens: Another opportunity for Elvis sightings, heee heeee!

Bad taste? I'll say! I love it. Fortunately or unfortunately (it depends on the person, I'm of the latter group), I've never gone to a "themed" party, other than a "Favorite Musician" dance way back in school. Where's the fun in that? The Monster Mash one sounds great.
I've been listening to that song on constant repeat for the past few days. Good stuff.

One year at work we did The Movies as a theme. A couple of co-workers and I were Men In Black. We did a good job, but that meant we wore suits to work on a day we could have worn anything!

We used to have a big Halloween party every year. A couple of years we themed it for "the sixties" and got some great costumes. Some friends of ours pulled off a really impressive Phillips and Mama Cass. We went as Shaggy and Velma from Scooby Doo one year and Endora and Maurice from Bewitched another.

I would love to go to a themed party- but I'm from a very small town and there aren't too many celebrations with the exception of the annual "Grape Fest".
I've seen the celebrity thing done before and the costume that most sticks out to me was a couple dressed as the Kennedy's..........I just think that's bad taste.