I have a strange curiosity with a certain aspect of the Gears of War 2 menu system, which is this: it's split into two stages.
When you host or join a custom multiplayer game, you're taken to the first lobby screen (or "Multiplayer party lobby" as it's officially called), where the host can choose game mode (such as Horde or Wingman) and options (number of lives, game duration). When the host is satisfied and selects play, you're taken to the second screen (or "Pregame lobby") where the host can then choose the map (players can also select character and starting weapon at this point).
There's a 5-10 second loading screen between the two. Which is odd as I can't tell what it's loading, if indeed it's loading anything at all (the game itself loads in the background once the map has been picked and the game start countdown reaches 0). It can't be loading the map or characters as they're picked afterwards.
Friends can't join the game once you're in the "Pregame lobby" either, though most games allow joining in the middle so it's not a huge issue, just another strange quirk of the menu.
It seems to have been designed this way so that they could fit all the options on screen rather than splitting them off into a separate menu and displaying a simple summary instead in the lobby.
Ultimately I think this could easily have been refactored into a screen for the lobby and an options screen for the host to configure the game properties. Whilst this is still two screens, there would be no cumbersome loading screen separating the two (and you would be able to travel back and forth between them without having to incur the wrath of the loading screen multiple times either).