Forget being a judge just go for the party atmosphere.
Forget WEED (yes I said it) The Dam has a lot more to offer than just the drugs and red lights.(The weed is always top there I just think your expectations work against you)
Leiden is very well known to me and well worth visiting along with Den Hague (the place for serious growers as it has the best grow shops)and of course the best place for live music is Rotterdam.