The USO ETF doesn’t have long term options, so you can’t go farther than July 08 right now. People often lose money on options because they expire before the expected price move happens.
Another possibility would be OIH, which is an ETF of oil service companies, such as drillers, etc. Options are available to Jan 2010.
I don’t think oil will see $20-30. Even if demand falls, you’re at the whim of OPEC. Heck, you’re at the whim of the Saudis. Then again, predicting energy prices is like predicting where the ball will land on a roulette wheel.
Just go to a casino. At least in a casino, you KNOW you’re gambling. Plus, free drinks!