Find a poker training site that lets you download their videos, and get as many as you can find for your game. Then don't just watch them, but study them. At every point a decision is made, ask yourself if you would make the same decision or not. Take notes. If you continued your subscription with the training site beyond the initial month to do the massive downloading, then ask questions about the video.
Go through old hand-histories with a fine-tooth comb. As poker players, we often neglect spending time to review in favor of getting in more hands. Now is the time to buck up and review the hell out of all the hands you've put in over the past few years. If you don't find several leaks that you could fix upon returning to the tables, then you're not looking hard enough.