How is a new currency created? Money is debt, it doesn't matter if you use fiat currencies, gold, or commodities. It is an overvalued one relative to its industrial uses, because it promises a greater utility for the owner in the future. The key point here is that you have to believe that you will be able to endorse the money  to another person when needed (Regression Theorem).

Do we use any new currency nowadays? Yes, bitcoins, BTC. Basically, it is a digital currency. It's widely used (100 million USD) with a predefined schedule release until 2140. It is possible to exchange it with bank notes or the use of credit cards through certain webs like MtGox. Of course you can find the exchange rate with the rest of the currencies or even draw their charts.

Advantages: privacy, low fees, limited creation. Problems: fraud, trust, technical failures, Government persecution.

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