Maybe once or twice, but it's been a long time. I don't remember where or when. It still mystifies me that people don't use any denominations higher than the quarter.
When I was a kid, my parents used to give me half dollars occasionally, as payment for chores/allowance. But that was back in the 80's, and I didn't even know silver was in coins back then. I wonder how many 64's I spent on candy or saving for Nintendo games. haha. In college, I worked as a cashier at a movie theatre for awhile, and I'd receive maybe one or two a month, and I'd give them back as change. Most people reacted then the way they react now when I spend half dollars, either "Wow! Cool, a fifty cent coin. Come 'ere and look at this." --or-- I get silence followed by a look that screams "What the #%@& am I supposed to do with this?" Whatever. At least I'm not giving them Susan B's. Then I really get the stare of death. Seriously, I'm surprised that the halves I search through are as worn as they are. Did they used to circulate more?
It was when I had the movie theatre job that I found a 1908 quarter in circulation. Still have it. It's about a G-4, very worn, but I was floating that whole night. It was in a clear-wrapper, sandwiched between a bunch of state quarters. A 1908 quarter! That's what got me into numismatics, which recently, got me into coin roll hunting.
And now is as good a time as any to confess something. I sometimes spend Buffalo nickels and Indian Head pennies, just to get them into circulation, and sometimes I throw in a few when I cash in rolls at the bank. Wheat pennies, too. Some in uncirculated condition, some not. I just like to wonder what happens to them. I'm already into coins, but maybe finding an old buffalo or a shiny Indian head is just what someone else needs to get hooked. The coins probably just get hoarded anyway. Oh well. I'm mainly into bullion and the thrill of the hunt.