CS Lounge
From KGB Wiki
Wean 5328 was once the CS Undergraduate Lounge. Many KGB people hung out there. In 2005 it was converted to classroom space, due to a shortage of space during the construction of the Gates Hillman Center. After that, people hung out in the Newell-Simon Atrium for a year, followed by the Wean 5207 cluster.
Nowadays people hang out in GHC 3000.
#cslounge is also a popular IRC channel.