alcohol - who knows, i don't really like to drink much and my tolerance is SO low that last time I got drunk it was off of four bottles of beer, my friend had to give me a little help walking (yes, off of FOUR beers) and that's pretty much when I gave up on alcohol
weed - who knows, i smoke enough weed to kill a horse on a daily basis
I know I've smoked 2 blunts back to back by myself before, and I've killed an oz in a day or two so many times...
acid - strongest trip I ever had was off of 3 hits of paper, but I think the most hit wise was 6
shrooms - I took 2 grams one night, tripped nuts, the next night I went to my friends house where they had a bunch of shit inluding 50 grams of shrooms (in capsuls) so I took 5 of those and a roll and we smoked *almost* a quarter bag of KB, also they killed off a whole bunch of alcohol but I didn't drink
ecstacy - just 2. I never wanted to be an etard, and I've only taken more than 1 tab at a time once
RX drugs - my most memorable episode was when I had 2 xanbars and 5 soma's. I'd never done xanax, i was at my house and didn't know that 1 bar would put me on my ass so I took 1 bar, the last thing I remember (vary vaguely) is thinking "this is fun, maybe I should take more!" which is not something I would've thought if I'd been in my right mind. So, I wake up the next morning in my bed, all the zbars and soma's are gone and my parents are telling me about how they found me crawling around on the living room floor at 3 am unable to walk or talk. that was when I gave up on perscription drugs