At home workouts

What do you do?  I am directing this question mostly to apartment dwellers with minimal space... I know I can join a gym but I want to find out good workouts at home.  I have my mini elliptical and some workout tapes.  I'm not a huge fan of workout tapes...

My thought is to start climbing the stairs to my apartment on the 12th floor.  Please leave comments with ideas of your favorite at home workout!  It'll give me another minute of activity as well as some creativity that I so desperately need!