Not sling golf per se, but I have a story involving disc golf and slinging. This weekend a handful of friends and I went on a short road trip to hit up a disc golf course and a brewery. I took a sling along, and intermittently throughout the day I was picking up random things from the ground and giving them a toss.
On one hole I had already thrown my disc and started spinning a big seed (or something, not sure what exactly it was) I had picked up. One of the other guys was getting ready to throw, and another friend said, "If you can knock his disc out of the air I'll give you a hundred bucks." Obviously I accepted the challenge. The guy throwing let his disc fly, I gave my sling a couple quick rotations and let that seed go a couple seconds later.
I wish I could say I knocked that disc out of the air, but I wasn't even close.

In the end I did show a sling in use to a few people who hadn't seen one before. And the battle between disc and sling gave everyone a few moments of entertainment followed by a laugh.