WHY DOES MY CAT KEEP DOING THIS?!?

My cat does this too. However, he does it for mainly 1 of 2 reason. He likes to be as high as he can (he even likes to be on the top of doors, with my help) and he LOVES warm places. TV, cable box, the chair we just got up front... whatever as long as its warm. Maybe this is what your roommate cat is doing.