Wow, I loved Decathalon. I used to play this game in the arcade and man, was I on fire! I had a secret weapon where-in I would use my leather wallet and flick my wrist across the buttons, wallet in hand. It worked like a charm and my friends and I would play this game like crazy. I wore out a wallet or two and loved every event.
It's set up like track and field and was, I believe, first available on the Atari 2600.
The graphics were very lousy on that system, as we all know. But the C64, from what I remember, did it justice. Playing it with a standard joystick can be dangerous though as you have to move the joystick back and forth as fast as you can to run. Some events, like hurdles call for an occasional button push as well for each hurdle, for instance. So again, depending on how agro you get with the joystick, they have a tendency to break pretty easily. Still, with a group of friends or even alone, it's a decent sports/Olympics style game.
I don't remember all of the events off hand but I remember the javelin being very fun. It takes some patience mastering
the timing of when to throw -as you're running, you push the button and hold it and the runner will tilt the javelin up. Release the button when the javelin is at about a 45 degree angle to achieve the best arc on your throw. And while you're running, it's obvious you want to get as close to the release line as possible. A pre-mature button push can dock you many yards and lose it for you up against the computer.
If you're going to get into these type of games, Decathalon is one of the early ones. Certainly one of the first of it's kind. I think it's important to go back to these 'dated' titles to remember how they came to be.
Anyway, I would download Decathalon just to have the memories of old school track games!