Beckman 204

A room in a building at Caltech. There's a mainframe computer there which Sheldon wanted to use, so he created a home made sign-up sheet and put his own name in every timeslot.

There are several buildings named after Arnold Beckman, a chemist who was instrumental in the founding of what is now called Silicon Valley and who invented the pH meter. These include the Beckman Institute and the Beckman Laboratories. None of these buildings are directly part of the Physics Department.