Weed: what everyone else said here, plus it can also have stimulus effects and can cause anxiety and paranoia often in newbies, but sometimes it just does that in certain people. Different types of weed may cause slightly different effects.
Cocaine: Definitely a stimulant: you won't want to sleep, some alertness thought it won't enhance your activity like marijuana. Its a boring/expensive drug- people just snort/smoke coke and don't do anything often. The feeling itself is short lived and requires immediately more cocaine to keep the high going. So the feeling is kind of a wellbeing- you feel good, almost a rush even. I wouldn't say relaxing. Its not really a performance enhancer- you aren't going to accomplish anything on it, watch people smoke crack, they just sit around a table and don't talk. Addictive.
Heroin/opiates: the most addictive drug hands down. The feeling is pure relaxing euphoria. A pleasure rush to make you forget your problems. Terrible long term withdrawals. Also a boring drug, however I have seen many a junkies go out and function and do shit after shooting up.
That about covers the addicting drugs.