When you are playing Mechwarrior or Battletech or some other such game involving giant robot walking tanks, and your robot gets a lot of its armour shot off, so that it is very vulnerable to enemy fire, it becomes a shed.
A slang term for an outdoor Amphitheatre used for live music concerts. Names so because of the roof that covers the pavilion seating. Those under it are in the shed, while the remaining concert attendees see the show from the lawn.