Shambles
Bluelight Crew
Also seen ones that Dopemaster mentioned above involving slicing open yer sack and pulling your bollocks out to play with. Some hardcore muthafukkers out there 

Er, I can feel yer pain regarding the bike accident, but what's so wrong with 2nd hand crack smoke?? (well it's no worse than 1st hand crack smoke anyway..)
As somebody mentioned elsewhere in this thread, it's not totally unheard of for addicts to shoot up other addicts' blood if it's got enough drugs in (discarded missed clottybloody shots - not transfusion stylee... afaik anyway) so in comparison sucking cracksmoke from someone else's lungs seems pretty risk-averse to me in comparison. That and would be pretty ineffective so less likely to cause addiction. HR innit.
In Facefuck Badness news...
my mate would do a pipe and hold it in for 30 seconds then cup his hands then his cousin would proceed to inhale it mouth to mouth then hold it in himself for 30 seconds -they would do that all night.
I have seen a lot but the most weird thing would be amputee porn (using stump of a leg as an anal dildo)
Also the BME / Spankwire challenge rates very highly, the actual BME site is very old & has been used for years & tbh a lot of it really don't fuss me these days.
I should also add the Dnepropetrovsk maniacs killing video (screw driver in the eye & stomach for example with added death noises made me feel a bit sick)
http://en.wikipedia.org/wiki/Dnepropetrovsk_maniacs
Japanese enema porn, anal prolapse videos & German gay BDSM anal fisting should be added to the list.
A guy running at full speed and falling onto a cricket stump, splitting his pants and putting a tear mark down the side of his arsehole, not the nice wooden cricket stumps you get, teh shitty practice ones that are steel.
You can sharpen your gear with a match book and clean it with bleach.
I like cum shots but bukake is narsty.