Just to list a bunch: PDP-6, Logo PDP-11/45, Minsky's 2500, Imlac PDS-1, GT40, Robotics PDP-11/40.
Random tourists could just pound on the door, and somebody would usually buzz you in without checking who it was, just to get some peace and quiet.
Lars, do you know anything about the wire wrapping robot that was on the 9th floor? Henry Minsky says he thinks either Holloway or Knight built it (Tom Knight would know), and they used it to make the CADR lisp machine boards. Those were huge freaking wire wrap planes, the size of a tabletop.
Here's Marvin Minsky demonstrating the 2500:
https://www.youtube.com/watch?v=c4kMzrDr4jQ
Cynthia Solomon's got a lot more amazing historic videos from that time:
Atari Cambridge Research- parts 1-6:
Introduction:
https://www.youtube.com/watch?v=CR2CwKculBU
Margaret Minsky demonstrates a gestural system:
https://www.youtube.com/watch?v=-Wq6SQTVM9M
It's 1984 and Ed Hardebeck shows a gestural system and Gary Drescher shows object-oriented Logo:
https://www.youtube.com/watch?v=ClKQHgIoLPc
A force feedback joystick, a puppet machine and a program of dance and body movement are presented:
https://www.youtube.com/watch?v=R3qPCZ5z0UQ
David Levitt shows the music box:
https://www.youtube.com/watch?v=ocwsVkqEKys
Music box with Tom Trobaugh and drum machine with Jim Davis:
I have heard about the wire wrapping robot, but not who made it. The boards were made by Augat.