MegaMillions Overlay?

[BigFishSmallCardRoom]

I was wondering if someone could do the calculations and tell me when is it +EV to play the MegaMillions lottery? What does the jackpot have to be? What adjustments need to be made to factor in the chance that you will have to split the jackpot? What about the payouts for hitting some of the numbers but not all of them?

Thanks,

Biggs

P.S. I'm not being lazy, I'm just not sure how to do the calculations.