Common hour is the hour each day that classes are not scheduled. This allows common time for club meetings, recreational activities, and special events on campus. The common hour is noon-1 p.m., Monday, Wednesday, and Friday and 1:45-3 p.m., Tuesday and Thursday. Special events at campus are usually free and open to the public.
For a calendar of campus events
http://www.events.psu.edu/cgi-bin/cal/webevent.cgi?cmd=listweek&ncmd=startup&cal=cal64