I hate running for cardio. Surely, there must be a better way. Enter Dragging Sled. Using the instructions in this thread, I built my own sled. What do you think?
Tire from my wife's old car. A piece of an old desk that fell apart years ago (particle board). A few bolts, nuts, and washers from the local hardware store. Add in a pulling strap and I'm ready to go. Cost me less than 5 bucks.