Disc golf is, for all intents and purposes, the same as traditional golf. but instead of hitting a tiny ball with a club, you use your body, to throw discs. Instead of aiming for a tiny cup in the ground at the base of a flag, you throw towards a basket made of hanging chains.
Clubs are replaced with discs. You have your drivers, your mid-range (kind of like your irons), and your putters. There are further sub-classes at more professional levels, but anyone can find a single disc they like, and play the whole game with that one disc.
You start each whole on a tee area (commonly called the tee pad), where you take your first shot, the drive. Moving down the fairway, your objective is to get it to hit those chains, and drop into the basket. Speaking from experience, the first time that any one hears that noise, from further than 10-15 feet away, they’re hooked.
That’s the simple explanation.
Disc golf is about getting outside, about enjoying nature, under all conditions, and having fun with like-minded individuals. It can be played by literally almost anyone, as long as you can throw a disc (notice no good/bad qualifier!). Most courses are generally fairly spread out, and in wooded areas, so there is some additional physical requirements, but it’s no more taxing than ball golf, and is drastically more affordable. As mentioned, you can play just fine with a single professional quality disc, which generally costs between $15-$20.