Spin Magazine's Rock Lexicon

Spin Magazine has a list, albeit brief, of some niche musical genres, and interesting definitions for them. Some excerpts:

DISCO METAL: This is up-tempo, semiheavy guitar rock that someone (usually a stripper) could feasibly dance to.

RAWK: This is how people who start bands in order to meet porn stars spell rock. It is also applied to long-haired guitar players who can’t play solos.

PROG: There was a time when “progressive rock” was easy to define, and everybody knew who played it—Jethro Tull, ELP, Yes, and other peculiar, bombastic men who owned an inordinate number of Moog synthesizers during the mid-1970s. ... However, just about anything qualifies as prog in 2005. An artist can be referred to as “kind of proggy” if he or she does at least two of the following things: writes long songs, writes songs with solos, writes songs about mythical creatures, writes songs that girls hate, grows a beard, consistently declines interview requests, mentions Dream Theater as an influence, claims to be working on a double album, claims to be working on a rock opera, claims to have already released a rock opera, appears to be making heavy metal for people who don’t like heavy metal, refuses to appear in his or her own videos, makes trippy music without the use of drugs, uses laser technology in any capacity, knows who Dream Theater is.

I know who Dream Theater is:)