Inversion table. I bought one today at Dick's Sporting Goods for $200. The product is better than the assembly instructions !!! After discussing this with two orthopedic surgeons, two physical therapists, a chiropractor, an acupuncturist, (can you tell I have a few back "issues"?) and viewed quite a few discussion forums, there were very few down sides shared. Mainly, some people's backs are SO screwed up (even after surgery) that they had problems right away and got rid of their tables.
After assembly, I watched the included DVD about how to use the table as well as the does and don't. I restricted my angle to about 45deg and time to about two sessions of 5 minutes. I could feel the pull at the belt line (numerous problems there) right away (as expected) and felt fine will "hanging" and after getting back to vertical. Now that I am sitting at the computer, it has taken longer before my back started to bother me. I'm glad I bought it, and I am planning on using it at least once a day. The "fun" will be after a a week or so of acclamation before I am hanging by my ankles. THAT should be interesting.