nah - you can get a changes in expected value with lotteries and situations where its possible to profit - its rather a skewed distribution so those situations require you to buy rather a lot of tickets...
Well, the only way it's possible to guarantee* a profit in a lottery is to buy a ticket for every possible combination.
For example, in the case of euromillions, there are 76,275,360 possible combinations. (according to the first hit on Google, I cba to work it out myself
)
At a cost of £2/ticket, buying a ticket for every combination on anything above a £152,550,720 jackpot will be profit.*
*There are a few provisos here:
a) this only works if you are the only person to win, if you have to split the jackpot then you will obviously lose at least half of the money.
b) I can't even being to imagine how you would cope with the logistics of buying 76 million lottery tickets (to put that into context, over a week that's just over 126 tickets per second)
c) if you had £152,550,720 available cash to buy those lottery tickets, I highly doubt you'd be playing the lottery...