Oh no, you caught me! [There's a joke here, and the joke is that they're actually both workaholics -- it's just a bit less obvious for Mephisto, since he does most of his work at night while most people are asleep. There's plenty of time for play when you've got 23 hours of the day.]

Ah, but now that my master plan has been found out, I'll have to come up with something to make it up to you, hmm... how does three wishes sound? All I ask in exchange is that you spend the next 24 hours taking it easy!

What do you say? Care to make a deal with the devil?

[This is surprisingly hard to say with a straight face -- he's already snickering a little.]