Philadelphia based (but later became nationwide) ECW (or Extreme Championship Wrestling), was created at the most perfect time. See, back in the early 90s, there were two wrestling promotions, World Wrestling Entertainment (WWE, but it was WWF at the time), and World Championchip Wrestling (WCW). These two groups shyed away from "real" wrestling (yes it's fake, but I mean the fake that looks like a real amateur-style match). Most of the characters in the two companies were basicly larger-than-life cartoon characters. ECW was the first comapny to bring back the "real" style of wrestling in bringing in the most talented technical and amateur wrestlers, but also created the style called "hardcore" (where different weapons, violence was used). It also let the performers be themselves or an extention of their personality, and not hide behind some stupid character.
The company also had the most rabid, un-PC, fans around. They were some of the toughest crowds (I was at a couple of their shows here in Queens NY), but they were also some of the most smartest, intelligent crowds around as well. What I mean is that they know what was good and would cheer/chant to encourage it. If they didn't like what the company was offering, they weren't afraid to voice their displeasure. Now, if you were the "heel" (bad guy) woman in the match, you got it worse. The fans and what they said wasn't meant to be personal, just a reaction to the character (which meant that the character was being done perfectly).
I used to stay up at night to watch this on the MSG network at 1 am Sat nights, this company got me back into following wrestling. This company had the perfect balance of the ultra-violence in their hardcore matches, but also had some of the best technical and mat wresling ever seen here in the US. As much as many don't like to admit, but the ideas ECW came up with (and were stolen and used by the "Big" companies) saved pro wrestling in the US, and also changed culture in general.
If you got $25 laying around and want to watch a well-done documentary on not just a wrestling company, but the American dream (one man creates something long lasting out of nothing), pick up this DVD. It also has a small sampling of their gratest matches (though I could name at least 10 other matches that should be also added to show the real history of the company).