Pres. Obama is scheduled to appear on an episode of Mythbusters Dec 8. The role he will fill? Identifying whether a myth they already busted in another episode is busted or confirmed. The myth has nothing to do with current politics, with Chicago or DC, with NGOs and fund raising or ... anything even remotely related to his job. Did Archemides burn down a fleet of ships with a mirror? No.
Why? To promote science education, a worthy enough goal if perhaps a very dubious way of going about it. Now if the myth had not already been busted and if it had anything to do with the Presidency, I would not give him a hard time.
Except of course imagine what model you have to believe in. Someone is on the margin between studying business or law and studying science. But now s/he learns that the President himself is on Mythbusters. This provides the necessary impetus for them to take an extra science class or declare a science major. I don't see it.
A little more plausibly, one of the President's youthful fans who has never heard of Mythbusters watches one show, then another and another. S/he is attracted by the pyromania... pyrotechnics of the show and moves over to chemistry to study such reactions. That's a bit more plausible: Pres. Obama as a gateway drug to Mythbusters as a gateway drug to science.
Update: Now appearing on The Daily Show makes more sense, but he probably won't be pushing science education there.