The Lecture Hall Cloud Chamber produces a sensitive area measuring 51 by 51 cm. This is large enough to produce a continuously active display of tracks from natural background radiation. It can be set up in about fifteen minutes. Fourteen kg of dry ice and 500 mL of ethanol will operate this display for over eight hours. Alternatively, 6 liters of liquid nitrogen will operate the display for one hour with our optional cooling tray assembly. Fiducial marks are spaced ten centimeters apart, facilitating quantitative measurements. Overall dimensions are 57 by 57 by 30 cm. Chamber is shown below with optional source port installed.