I was reading "Debt: The First 5000 Years" and learning about how money did not arise from the need to provide a better system of barter, but arose out of the need to better account for debt that was already present.  I still haven't completely wrapped my head around the notion, so I may have it wrong here, but this bit of an article about alternatives to the euro in Greece caught my eye:

Members start their accounts with zero, and they accrue credit by offering goods and services. They can borrow up to 300 TEMs, but they are expected to repay the loan within a fixed period of time.

Battered by Economic Crisis, Greeks Turn to Barter Networks

The new (virtual) currency is ostensibly tied to the euro (1:1) but does not require any actual euros to get in the game.  I would assume there is no way to cash out either. :)

But my point here is that the creation of "money" does not require anything at all except the accounting of who owes how much.  Money is debt.