Cameron and Tyler Winklevoss are at it again. Only this time, they want to create what amounts to an exchange-traded fund, or ETF, for investing in Bitcoins. Frightened? You should be, says Fool contributor Tim Beyers.

To be fair, the Winklevoss twins aren't the only ones trying to cash in on the Bitcoin bubble. Lamassu Bitcoin Ventures has built an ATM it calls the "Bitcoin Machine" that transforms currency from any of 200 or so countries into Bitcoins on the spot.

Some 60 distributors have already expressed interest in the device. Meanwhile, the market for the digital currency gets weirder by the day.  An accused scammer recently tried to dodge SEC charges by claiming the Bitcoin "bank" he ran didn't actually deal in real money. A federal judge has since deemed Bitcoins to be as real as cash.

Just don't let that be an excuse to buy into the Winklevoss' ETF, Tim says. There are better alternatives. In the following video, he lays out the case for a stock poised to profit handsomely from the long, slow switch from cash to digital substitutes. Please watch to get the details, and then, using the comments box below, weigh in with your own ideas for beating the Bitcoin bubble.