OpenArena Community Mappack (also called OACMP) is a series of mappacks containing GPL'd maps made by the community itself. The idea is to give GPL servers something else to play aside of the official maps and the already GPLv2'd maps.
This idea started in the official OA forum.
Unlike some other mappacks around, this is not just a compilation of existing Q3/OA maps with different history and licenses found around the net, but a series of maps designed and tested appositely for this mappack, all GPLv2 compatible.
OACMP packs cannot be considered official OpenArena releases, however they get close to.