1. Football (computer) games which include the offside rule. I remember the days when the offside rule was too complicated for consoles/computers to handle and many was the time that you'd have to argue that "that goal didn't count 'cos it was offside". I hope you youngsters out there realise how lucky you are to have been born in an age where computers are advanced enough to understand the concept of offside and to be able to apply it in practical real life situations.
2. I dunno, lightbulbs n electricity n stuff. Imagine living without lightbulbs!