Maitrea is an amazing vegetarian restaurant (open for both food and just drinks). The restaurant is run according to Buddist principles. Enlightened people can get a meal for free. Non-enlightened people will be delighted to know that the atmosphere is not one of religious austerity and alcohol is served! I tried the Hemp Beer, but would only recommend repeating the experience to fans of hair shirts. On the other hand the walnut and chilli hot chocolate is a sublime, intense shot of chocolately marvellousness. The mulled apple juice was also lovely. The wine is good.
Food is reasonably priced and includes vegetarian twists on Czech classics as well as internationally inspired vegetarian dishes.
Also, don't miss their fairtrade Mama coffee - it's one of the best coffees I've ever tried.
Maitrea's decor is also very cool. It's designed according to Feng Shui principles. Whatever you think of Feng Shui, the design is beautiful and restful. There are two fountains and a fireplace. The wood of the bar is beautifully curvey. This was my favourite place to eat in Prague.