$267 million

and approximately 1 in 176 million odds of getting the right numbers. (not counting the chance that another ticket will get the same number or that there will be partial winners etc reduces the "rational investment" argument but...) http://www.illinoislottery.com/numbers.asp (Mega Millions)

So I just put a dollar into the office lottery ticket fund. I wasn't going to because I'm 100% certain, beyond any shadow of a doubt that we will not win.

BUT. IF. Somehow. The office were to win? and I was one of the only ones not in on it? damn.

The downside risk was too much. $1 was a good investment against being left behind. Just in case.