TBT isn't exciting enough for me, but I think the best way to play any move in these ultra ETF's is to sell options if the options are liquid enough. They usually have a very good premium because of their inherent volatility.

Instead of just buying the ultra shorts, I sell naked calls on the ultra longs. Because I collect a large premium, I can be somewhat wrong and still make money. I prefer to sell calls as opposed to selling puts on the opposite ETF. If one of these gets assigned to me, I would rather be short. They are, after all designed to fail.