I mined about 13000 bitcoins in 2010 when it was possible to mine with a single quad core CPU. It was worth about $100 when I stopped mining in August 2010, and I was ecstatic that I had earned a nice steak dinner for doing absolutely nothing. After I missed the first peak at $31 in 2011, I was determined to sell everything if it ever hit that price again.
Unfortunately, little did I know the price would surge to $145, and I sold most of my stash at the then all-time high of $40-50.
Not quite a bitcoin millionaire, but still a good chunk of change (of which a sizable amount will be going to the IRS).