This is a pretty interesting article about actual lottery AP's. Apparently one of the games has a sufficient progressive payout (non-jackpot) to make it +EV. People buy hundreds of thousands of tickets to damp the variance to an apparently reasonable level. I'm surprised this is even possible given the high taxes.
http://www.boston.com/news/local/ma..._with_a_windfall_for_a_knowing_few/?page=full
http://www.boston.com/news/local/ma..._with_a_windfall_for_a_knowing_few/?page=full