Microsoft and Epic have made the Gears of War 2 Flashback Multiplayer Map Pack available to everyone on Xbox Live Marketplace.
Every copy of Gears 2 ships with a redeemable code that can be used to download the pack for free, so presumably its availability is designed to wring money out of the second-hand games market, or punish idiots who've lost their code.
Said idiots will have to pay 400 Microsoft Points (GBP 3.40 / EUR 4.80) to download the pack, which consists of five maps from the original Gears of War.
These are Canals, Gridlock, Mansion, Subway and Tyro Station. We've always been a bit partial to Gridlock and Tyro, as it goes.
The pack is 116MB in size and if you've left your Xbox 360 on at home you can set off the download via the web-based Marketplace.