Study room between Mills and Dennett 4 in Mission Park. So named after having been slept in by "Uncle" Jeff Kaplan, pseudo-JA and mentor to Dennett 4, during First Days orientation of 2007. Despite the fact that Jeff spent only one night in said study room the name stuck, and has become a part of D4 (sometimes M4) vocabulary.
"Where's the vacuum?" "Probably in Uncle Jeff's room." "I've got mad reading to do. I'll be in Uncle Jeff's room." "Who is that man asleep in Uncle Jeff's room?"