Backwards Compatibility?

I had an original Xbox back in the day and still have the stack of games. I heard some of them can be played on the 360, so I plugged my 360 into the router and inserted a game like it says to do online. Nothing. The first game it said it needed to update. So it did. After that it's just an error for every game off the list. Do I need a gold account or some special paid service with Xbox to do this? I just want to make a few of them playable for the wife and I.