Paris Is Burning is a really fun to watch documentary about drag queens. It was released in 1991 and you'll hear them bring up lots of slang that people here consider 'ATRL slang' but its actually drag queen slang and that movie is proof of how old it is.
Wikipedia it. It's a great movie but it took me three different sittings to watch it because the first 25 minutes or so are so uncomfortable. It's really good though and JGL is great in it.