Constructing a room divider is always a tricky feat, especially if you're renting and don't want to leave any permanent marks behind. One clever hacker managed that trick using a couple of poles from IKEA.
At IKEA Hacker, Andrew details via a series of photos how he used two $60 Stolmen posts as the basis for a full-on room divider. It's not a casual project, but the end result is very impressive.
Stolmen Post Room Divider [IKEA Hacker]