This map. Love it.

The name of the map is Tanks Playground. You can find it in the Steam workshop for Left 4 Dead 2. :)

People in the video:
Patrik: http://www.youtube.com/LAGxPun1sh3r
https://twitter.com/LAGxPun1sh3r
Richard: http://www.youtube.com/LAGxNinjapwn3r
https://twitter.com/LAGxNinjapwner

Twitter: http://twitter.com/#!/LAGxPeanutPwner
Facebook: http://www.facebook.com/lagxclan
Second Channel: http://www.youtube.com/user/LAGxPeanutLegend
Tshirts and stuff!: http://lagx.spreadshirt.net/
Twitch (Livestreams): http://www.twitch.tv/peanutstreams

Music used
Outro: http://www.youtube.com/watch?v=fBWaccRAdBQ
Outro Artist: http://www.youtube.com/RamesesB