I'm studying abroad in Prague for the next three months and have been searching around near Charles University for a good place to spend two hours in between classes. I stumbled upon anticafe rather randomly as I was looking for somewhere when I stumbled upon this gem.
What a find. The logic of it is something I haven't encountered--you get unlimited drinks (coffee, tea, maybe ice cream?? it's on their door at least but I haven't tried) and snacks (mostly cookies, candy, etc) and all you do is pay 1 kC/min that you spend there. So you pay for the time that you spend there. This is apparently only a spring deal right now so get on it if you can! It'll go up to 2kc/min after the promotion unless you buy a membership card for 50kc--then it'll be 1.5kc/min.
Anyways, the lattes are great, and the biggest sell for me is the extremely fast wifi--it's actually better than what you would experience at Charles University. All in all, it's an awesome place to just hangout and chill with friends. They have a playstation, wii, a lot of board games, a fooseball table, and more. It's just a generally great cafe. Have a few lattes and you'll probably be able to pay off the entry fee. They've only been open for 3 months and it doesn't seem like too many people know about the place. I've talked with one of the workers and she tells me that the Czech aren't too fond of the business concept, but I think it's a great place to get good coffee and to just spend some time.
tldr; great cafe--pay 1kc/min that you spend there for unlimited drinks and snacks, absurdly fast wifi read more