What's the Difference Between Nominal and Real?

I don't know how many times I've been asked questions similar to "What's the difference between nominal and real?" since I started working for About in December. Terms like real interest rate are used all the time, but quite often students are unsure what that term means. So I finally decided to create an article explaining the difference, called simply "What's the Difference Between Nominal and Real?". It should be useful for all the freshmen starting their first economics course this September.