Buy stock in a company that's down, but unlikely to fail and utterly essential to the future of the world.
I'd say buy Intel for instance. Their stock is at a historically low point (or close enough), they're too big to fail, still doing rather well among the big tech companies, and are bound to come back someday. Maybe not in the next couple of years, but eventually. They may still have a bit more room to drop though, depending on how the beginning of this year goes for them. Still, I'd say it's a safe bet, at worst, you don't lose anything in the long run, and at best you could probably quadruple your money. (assuming you outpace the devaluation of the US dollar)