craftgrrl | Looni Uni, with yucky halls

Im going to Uni in september, and I chose the halls I wanted the first time i went to look around, because I fell in love with the amazing view of the lake and the park, but frankly the room is yucky. Ive already got some sari fabric to hang / pin over the brown curtains like a pelmet/droopy thing, to atleast cover them when the curtains are open. Ive looke in the FAQ and was wndering if anybody could give me some advice on covering the walls, i wanted to have something like a giant piece of pop art on the wall, and was thinking about projecting something onto a sheet and painting it before I go, but my local artists place are selling canvasses cheap, and was wondering if anybody had a good idea on how to hang the canvas without putting holes in the walls, or on any alternative wall coverings, because the walls are brown too, eww.
Cheers
xxx