Prague is stiff with things to see and do, so long as you stay in the old parts of the city. When looking for restaurants, remember that many of them - and many of the best of them - are underground. Finished caves under the streets and buildings, with torchlight and pillars, the works. Very cool. I'm afraid I don't remember any names, but if you explore you should be fine. Hit the basics as well - the the castle and cathedral, the central square, the Charles Bridge....It's all good.
Beer is everywhere there; the locals drink it for breakfast. Each restaurant has a single brewery supplying it, and each brewery produces two beers for this purpose - a light and a dark lager. So you just order a 'dark' or a 'light' beer. I never got any bad ones, though some were better than others. The restaurant doesn't necessarily advertise the brand they carry, so I'm afraid I can't give much advice here, except to try different places. Like I said, you won't get any bad ones.
Absinthe and cannabis vodka are in every liquor shop as well; they are generally advertised boldly, as these products are often exotic to tourists. Neither has any significant psychological effect (except for that of alcohol), so don't be too afraid to try them if your'e curious. Absinthe starts to have a mild mind-altering effect if drunk in large quantities, but again, it's nothing major.
I would recommend visiting the U Fleku beer tent at some point. The place has a very old heritage. They brew a beer that is only served there, and sell it by the ton. During peak times, dozens of servers scurry about carrying trays covered with pints of beer, which they fling in front of anyone who doesn't have one. You need to tell them explicitly to stop if you've had enough. It is quite good, and the food is wonderful beer food. Terrible for you, but wonderful. They have wandering musicians, and locals often sing along and dance on the tables. A bit of a pricey place by Czech standards, but it should be tried once.
Get a Frommer's guide if you don't already have a guide. It will give you more detail, and tell you much that I left out.
Na zdraví!