This is a Counter-Strike: Source map. It's a copy of the original Pac-Man level, with 16 terrorist spawn points and 16 counter terrorist spawn points in the map. The bomb target is in the middle, where the ghosts spawn in the original Pac-Man.
TO INSTALL: Place the de_pacman.bsp file in the "C:\Program Files\Steam\SteamApps\USERNAME\counter strike source\cstrike\maps" folder, if you've chosen the default steam install location. Replace USERNAME with your steam username. Then you can create a server and play.