US Mint: Commemorative Coins lists an additional trove of collectable US coins, with a bit of interesting history.

My dad left us a "Stone Mountain Quarter" (at 1925 at the link) that he picked up on a visit to my sister in Atlanta some time back. He said he was told when he got it that they were "rare" and no more could be made; but this is the first explanation I've seen regarding why no new ones could be minted - and the first claim that I've seen that the "quarter" is really a half dollar(?). I guess I should dig it out and take another look at it. My recollection is that it's in only fair condition, and I'd probably have to take it back to Atlanta to find anyone interested in it; but I've been waiting for GA to "get over" the war before venturing there again.

John