We know Gears of War 3 was going to bring plenty of multiplayer downloadable content even before the official announcement. What we didn't realize was that we would seemingly get a sneak peak at the potential names of upcoming multiplayer maps through an accidental back door.
Joystiq notes that by looking at the Horde leaderboards, you can find three maps called Azura, Rustlung, and Blood Drive. Azura is a location in the Gears 3 campaign, while Blood Drive is a popular map from Gears of War 2 that's probably set to get new life in this iteration.
It's worth noting that we don't know for certain if these are future maps, but it looks promising. Currently all of the maps are inaccessible, and most are completely empty. Azura is the only one with any names listed on the leaderboards, apparently populated by five Microsoft testing accounts.