Okay, tasteless jokes aside, I would suggest sitting somewhere calm, smoking a cigar and drinking a beer. One of the most relaxing things you can possibly do. Also, DO NOT INHALE THE CIGAR. Just puffing it is a lot more relaxing, and there is much less chance of getting sick.

If that doesn't work, then yes, I- notice I say I here- do like to smoke some grass. However, do not do this unless you are already comfortable with the practice. Don't assume you can just go smoke a joint for the first time and instantly feel relaxed. Anyone here who has smoked pot will tell you that is a very bad idea.