Most of the usual thought experiments that justify expected utilitarialism trade off fun for fun, or suffering for suffering. Here's a situation which mixes the two. You are offered to press a button that will select a random person (not you) and torture them for a month. In return the machine will make N people who are not suffering right now have X fun each. The fun will be of the positive variety, not saving any creatures from pain.
1) How large would X and N have to be for you to accept the offer?
2) If you say X or N must be very large, does this prove that you measure torture and fun using in effect different scales, and therefore are a deontologist rather than a utilitarian?
A lower bound would presumably be the amount of fun the show 24 provides on average, with N being the ratio of the shows' viewers to prisoners rendered so they could be tortured. (Take That, other side!)