LOL I was thinking the same thing.
Most of the ideas here are good attempts but would either cause wider adoption on global basis, a rise in the value of Bitcoins or wind up being irrelevant. One of the more plausible would be cracking down on the exchanges and payment services such as Dwolla, but there is no absolute necessity to convert Bitcoins to any other currency once the incentive to use BTC over EUR/USD/JPY or what-have-you is great enough.
If you take away my livelihood, I'll go make my living somewhere else. In other words: if my money is worthless, I'll use a different money.
There has never been any measure fully successful at outlawing an alternate currency in any nation that has seen its legal, domestic currency lose value. Bitcoin is even more surreptitious and insidious to a government than physical pieces of paper. The usage cost of Bitcoin is so minimal that it completely trumps existing currencies.