Pot is as far as I will ever go to be honest. Other drugs can really fuck you up. Smoking pot once every few weeks (like I normally do, tho I actually haven't smoked since New Years) won't hurt you. Personally, I find it ironic that alcohol is legal when it is more dangerous than pot. (Alcoholics can get violent, dependent, and tend to be more active when under the influence)
I also took a few more Codeine pills than I should have once, I was sick, and I was tired of being in pain, so I downed a bunch. Needless to say I wasn't feelin much after that.
Edit- My ex-gf robo-tripped on Nyquil one time and got really messed up. She puked her brains out, and has never since been able to take any cough medicine without going into violent bouts of vomiting.