Man set to win on 'lifetime' bet, from the BBC.
In April 2007, a British man, Jon Matthews, was diagnosed with lung cancer and given nine months to live. He placed a bet with a bookmaker, William Hill, of 100 pounds at 50 to 1 odds. He's still alive, and he's collecting his 5000 pounds today.
Now, I have to think that the bookmaker offered odds which were much too long. Assuming that "nine months to live" actually means anything, I'd guess it's the median survival time. So this man had a probability of something like 1/2 of living the nine months. The bookmaker should have been offering 1 to 1 odds. (Actually, not even that, because they've got to make a profit!)
And even if it's the mean survival time that's meant, I doubt the distribution is sufficiently skewed to make a real difference. I suspect that "you've got X months to live" is just something that doctors say to patients informally, though, and it may not be sufficiently well-defined to quibble about this.
Of course, as the article points out, bets like this don't get made often. If they did, the bookies would pretty quickly figure out that they shouldn't be offering such large payoffs.