Lunch was at a little restaurant near the west end of the Charles Bridge, U male velryby, which means "the little whale". It came highly recommended by my guidebook, and I would second that. For the benefit of my wife, here's their menu (click to see it at a readable size):
And here's what I got:
That's the spicy wings and the grilled mussels from the tapas menu (the wings were just OK, but the mussels were great), and the char-grilled tiger prawns main, a dish I wouldn't usually get, but which my waitress recommended so fervently that I decided I had better try it. It was very yummy, although I felt sad not to have tried all the other yummy things on the menu; it wasn't good enough to eclipse that sensation. The potatoes came with the prawns, and were really nice; buttery and flavorful and not overcooked.
I'm not exactly sure why I feel this way, but my sense is that this is a really fantastic restaurant that I barely scratched the surface of. It's only a few blocks from the Charles Bridge, but the tourist mob is completely unaware of it; not only did no other tourists come to the restaurant while I was there, no tourists even walked down the street! The food was prepared with real care and skill, and the dishes that didn't completely resonate with me are dishes I don't normally order anyhow; I think it was my fault, not theirs, in other words. The next time I'm in Prague I will make a point of going back. Little whale, we shall meet again.