2007 might have been a good year to deposit $65,535 in your checking account -- if your bank was using Excel 2007 to keep its books. Red-faced Microsoft officials were forced to admit that that particular version of the spreadsheet would yield the number 100,000 when confronted with calculations that were supposed to result in, or be close to, 65,535. Microsoft blamed the flaw on a floating point error -- i.e., Excel 2007, like many high school math students, put the decimal point in the wrong place. The company issued a patch to fix the problem.
Further reading: IT Hall Of Shame, Part 1