Got one of these in my Christmas stocking...
http://www.fitnessanywhere.com/
After an initial play I am most impressed - makes it easy to work out just about every body part - on the road, in hotel rooms, or at track or park just after an interval session. It's really nice to be able to do a 'low impact' yet functional workout after pounding a lot of miles.
Is anyone else using these? I'm particularly keen to know which exercises and progressions work(ed) well for a runner.