You have a spare? Awesome! Or...do you have a water chair? Hmm. I can't imagine that would be too terribly awesome, though. I mean, I had a water bed throughout high school and college and, while fun they get a bit sloshy for sitting in. On the other hand, it's clear to me that the water bed was the true inspiration for the Select Comfort bed, so it might be a necessary development before we can all have true, adjustable glute comfort in our offices and our sitting rooms. Tragic, really.