This thread is for everyone to record their “best” falls. I’ll start.
So I was riding down the street from a house I had been visiting, going relatively fast on my 36er (13MPH) and realized that I had forgotten my sweatshirt. For some reason I had a false sense of urgency about the matter and attempted to stop from my 13MPH pace immediately, and I leaned backward, only to accidentally turn to the side and slide about 10 feet, like a pro baseball player sliding to 3rd.
The odd thing about this time I fell is that I knew it was coming but I still did it! Thankfully I was unscathed, and was smiling as I remounted to head back up to the house to get my “forgotten” sweatshirt, before realizing that I was wearing it. Rather a pathetic endeavor really, but I thought it was fun! Not my most epic fall, but certainly the most fun I’ve had… falling 
My two would be jumping a wet table, and my tyre slipped right on the edge causing me go down twisted my cranks and almost broke my growth plate in my foot…
two or three weeks later I tryed doing a massive gap on my trials course… crank grabbing the pallet I as aiming for my same foot either got a massive shock from it or I bend it to much to the side and could hardly walk on that foot again after been in a cast for week…
My best fall is one of two, the first one being much more enjoyable.
I was on a group Muni ride w/ the Berkley club and riding downhill when it suddenly gets steeper and the uni starts to accelerate past the speed I can pedal so I decide to bail. I ended up doing a nothing coast for 2 1/2 revs before landing on my but 
The second I was riding Mt Berdel in Novato, and there was some squeaking coming from my left brace (see avatar) I looked and didn’t see anything wrong so I continued on (In retrospect I bet if I had taken it off and thoroughly inspected it I’d find a large crack, then I’d turn back and get it fixed). About a hour later the trail started to become a narrow trench and I doubted I could ride through it w/o the pedals on either side hitting. So I step off, but I put my foot on the edge of the groove where it was sloped at 45 degrees w/ my left foot and my brace snapped in half. Now my brace can’t be fixed, haven’t Muni’d since and wont be able to untill I get new braces (I now have multiple cracks in the other one.) 
i’ll just post the video…
this was in school - before you ask we did have permission to film (we weren’t accurate about what we planned on filming)
http://www.youtube.com/watch?v=DN7Y-WctlJI