I thought Bitcoin was a really neat idea as an experiment of a completely market driven asset. It seems like it still could become/already is that (I think this is called the "digital gold" idea).

Of course when the mania settles I have no idea if the value of digital-gold-sans-gambling would be $5 or $500,000 or $0. But I do think there is a neat idea that isn't just a pure scam buried in there.