Another reason not to buy DVDs. If you buy something, you should be able to play it regardless of where you are; this nugget of common sense seems to have escaped the money and power hungry DVD industry. DRM s*cks!
In the crazy world of DRM for DVDs, there's this idea that a Hollywood studio should be able to tell you where you're allowed to watch a DVD after you buy it. They accomplish this with something called "Region Codes." Discs have region-codes and players have region-codes. If you have a Region 1 disc (US and Canada) and a Region 2 player (Europe), and you put the disc in the player, the player will reject it.
But what happens when you take your laptop from New York to London? You're in Region 2, but you bought your device in Region 1. Can you buy a disc in London and play it on your computer?
Yes and no. When a computer manufacturer gets a DVD-decoding license from Hollywood's licensing cartel (the DVD Copy Control Association or CCA), it is allowed to make players that can change regions up to five times.