If "reverse Polish notation" sounds like the punchline to a Jackie the Jokeman routine, you obviously never enjoyed the unique thrills of Hewlett-Packard's line of scientific/financial hand-held programmable calculators. Sort of the missing link between slide rules and Lotus 1-2-3, the HP-12C (financial) and HP-15 (scientific) could be found in many a college student's book bag back in the day. Nowadays, the HP-15 has gone the way of the Timex Sinclair, while the 12C (still one of HP's best-selling calcs) retails for a steep US$80.00. Put that in your calculator and amortize it.
Not to fear — HP has realized that it's Steve Jobs' world, and we just live in it. So they're now offering iPhone/iPod versions of the 12C (US$14.99) and 15 ((US$29.99). Unleash your inner Gordon Gecko! Or inner computer nerds from WAR GAMES! Your choice.