Last night I went for a massive late night wonder round Prague with a friend I made at the Youth Hostel (I've been staying at the A-Plus Hotel & Hostel - which is a little out of the way but otherwise just excellent [and right on the Red 'C' subway line, so very accessable]) .
We walked for miles (over 3 hours) from 10:30 around the center taking in the sights, back streets, the end of a silent film, the castle, the Jewish quarter, a open air photographic exhibition and more. I was in my shoes for the first part, but they're not exactly comfortable (the only pair I had seeing as how the AirFrance had lost my luggage) so when we reached the castle I decided to de-shoe and return to normality. A relief I can tell you.
This was the first time I've walked around properly at night (I'd briefly walked a little way in Brighton) and I was surprised at my confidence in doing so. It's surprisingly easy to pick out the glass to avoid and the smooth cobbled streets of Prague make it very accessable.
I should also point out that after 10 at night is the time to see Prague's old center. The grockles have all returned to their plush hotels leaving their grockle traps empty and the crouds have dissapated leaving a city quiet and empty for you to explore. The only activity is a few people on evening stroles and the street cleaners (who do an excellent job). The castle was simply dessolate, yet still open to visitors to wander through, amazing!!