Amsterdam, I wanna go back, lol I loved it there.
You will see lots of interesting things there. The best are the "Coffee Shops" these are the shops that sell marijuana and you can recognized them with a pot leaf sticker inthe window, coloured white red and green I believe. There are lots of shops around, the smaller ones tend to be better with a different variety than the " chain shops (ie: bulldog, if I remember right).
We stayed just on the outside of the in the district. There is where lots of the action is. Our hostel (global Sports Cafe, really cool place to stay and cheap) was across the street from a coffee shop so we always started our day there, lol. If you into the sex scene check out the redlight district. For smoking you want to get into the grey area I believe it is called. They have head shops that sell the mushrooms, peyote and other mind drugs. The coffee shops sells marijuana and hash from all around the world. You can purchase a certain amount and either smoke it there or take it with you.
The best thing to eat while stoned are called a "toasties", basically a grill cheese with ham in it, but they use a sandwich press, lol. Great stuff. There are so many places to smoke at and buy it, they are all very unique and cool. There is so much to do and see in Amsterdam I could go on for hours, lol.