It is a simple equation, but needs a bit of prep work. Go to your favorite sport store and get yourself a starter kit for disc golf. They run at about $20. It will usually contain a driver, a midrange and a putter frisbee.
Then go to a disc golf course, there are a few courses in the Bay Area, and throw your frisbees around. To find one course near you go to http://www.dgcoursereview.com/browse.php.
We recently went to Hellyer Park again, a well maintained 9-hole course.
You can play for free the first times, but should consider dashing out the $25 yearly fee to the Silicon Valley Disc Golf Club: http://svdgc.org, which pays for a yearly membership that is tax deductible. Other courses might charge you a Green Fee, so this is a pretty good deal!
You are still wondering what it is? Well, disc golf is similar to golf as an advancement through a course with different baskets to reach. It is much easier than golf and a lot of fun.
If you are looking for a casual sport that is not too strenuous but gets you out to have some fun with friends you might want to consider disc golf.
Have you ever played disc golf before?