Where can a watch a game of Dungeons and Dragons?

http://www.youtube.com/watch?v=ES7DAvgNy7A and yes, that is how this works. other groups may be more serious and to the point, but this is fairly typical

http://www.youtube.com/user/dndhouston This group has been putting up videos of their full games and they use a variety of systems (though recently they've been sticking to 4th edition I think). These videos have the camera focused on the playing surface of a battle mat rather than focusing on the players. However an alternative, is RPGMP3.Com. The files there are all audio, not video sadly, but they do a very good job of capturing the flow and feel of a game. There are a ton of sessions (from multiple groups, which will give a wider range of play styles) of many different game systems, from Dungeons and Dragons, to Rolemaster, to Warhammer (the RPG not the wargame) to any number of smaller indie games. If your imagination is up to the task I highly recommend giving them a listen. I listen mostly on long car/train/bus rides and at work when it's slow enough. A session can last anywhere from 2-6 hours or more but most fall into around the 3 hour mark