Happy, I realise most people can consult Google and that is fine, it is why I assumed this thread would not kick off, as is the case. But still worth a look for some of the newbs. At least they can post questions if they do not understand, unlike if you read google and end up more confused than when you started. Its hard to find some simple information sometimes out there on the world wide web.
Here are a few I have used lately:
YM - Mini/sized Dow. The YM trades on CBOT (Chicago Board of Trade) until 5pm Eastern Time and reopens for trading just over 3 hours later at 8:15pm. The contract months are March (H), June (M), September (U) and December (Z). THe YM moves in increments of one point, which is worth $5 per contract. Margin is around $2,000. This contract trades nearly 24 hours, however traders genearlly focus on the cash market session from 9:30am to 4:15pm.
ES - E-mini S&P. The ES trades on CME (Chicargo Mercantile Exchange) until 4:15pm, and reopens 15 minutes later to start the next session. There is also a shutdown period from 5:30pm to 6pm. The contract months are the same as the YM. The ES moves in increments of 0.25 points, which equals $12.50 per contract or $50 for a full point move. Traders need around $2000 for margin. Most traders focus on cash hours, which are the same as the YM, despite the ES being open nearly 24 hours.
PPP - as bvb fan has stated, Purchasing Power Parity. If price discrepancies exist between price level in two different countries, their exchange rates will adjust to ensure prices equal. I.e. an increase in relative inflation in one country leads to a decrease in the countries currency. This is however, theoretical upto a point, as trade barriers, transport costs and differences in taxes can alter prices. Sometime inflation is not the driver, but the expectation of inflation.
IRP - Interest Rate Parity. If the interest rate on American bonds falls relative to the interest rate on Australian bonds, then the US currency will depreciate against the Australian dollar.
Both of these can be seen recently, with the US lowering interest rates, causing a depreciation of their dollar, and Australia targeting inflation, causing a relative increase in the Australian dollar (I realise there are more factors in play than these two on the AUD/USD, however this is the basic premise for beginners).