Wahoo Walls is a basement finishing paneling system. It is water and fire resistant, supposedly has an insulation value of R13, and takes care of 4 of the most brutal steps of DIY basement finishing (framing, insulation, drywall hanging and mudding) in one step. It's paintable and doesn't have the ugly seams that many basement finishing systems do.
Have an empty wall? Cover it will slim mirrors, they are cheap and easy to hang. This will have all your guests talking, plus it really adds a lot to your room. These mirrors can be purchased at Target or Wal-Mart.