I was watching a band play at Skully's a little over a year ago and this drunk kid kept running through my group of friends and just being a dick (mouthing off to anyone and everyone around us) between bands. I eventually went up to him and just said "Hey man, I don't know what your problem is but.." and before I could finish that sentence, he swung at me and caught me in the back of the head somehow.
I wasn't looking for a fight at all but after that happened I snapped. My one punch connected with his jaw and started coming towards me again. At that point, I realized I still had my beer (bottle) in my other hand and a quick montage of every movie bar fight flashed in my head and as he came in, I moved a bit to the right and broke the bottle over his head (well, it didn't break in that awesome way, but the bottom of the bottle broke off).
After that, it was done and my adrenaline was still running crazy so I threw him out the back patio onto the concrete in what resulted as the worst thud sound I've ever heard. He was carried out and I was able to stay and watch the rest of the show because I had people vouching for me.
And yes, what I'm saying is I got knocked out, Sam.
Other than that, I think the last actual fight I was in was probably back in middle school and I got my ass kicked.