I used to work at a company before the stock bubble burst and I was vested in 65k shares of company stock with a strike price of $6. I left that company in 1998 and the stock was at $4 - it didn't make sense at the time to buy any of my options. Well during the height of the bubble, the company's stock reached $60 a share.
65,000 x $54 (price after subtracting strike price) = $3,510,000
I've lost a few nights of sleep over that one - my one and only opportunity to hit some big $$.