QUOTE(Nechama @ Nov 8 2007, 01:21 PM)

sure, what about investing a computer printer that prints dollar bills?
Oh wait, that has risks of being arrested for counterfeiting
As well as the risk of the printer malfunctioning, the US changing the dollar bill design and cancelling current designs, the US dollar losing all value due to some odd reason, the possibility that they will stop making ink cartridges for that printer model, inability to get more paper, loss of electrical service to the entire planet, etc.
Note that while most of these risk are negligible, they are not zero risk.