Some Obama Marginalia
1. In 2001, Barack Obama appeared on public TV to give a restaurant review.
2. This coming Wednesday, he'll be appearing in the new issue of Amazing Spider-Man. One commenter says that Marvel didn't alert the retailers beforehand, so they didn't order any extras and should sell out quickly (at least until the inevitable second printing comes along).
Here's a big list of cameos by real people in comic books... my favorite was Henry Kissinger coming in on Dr. Doom's side in Super-Villain Team-Up #6-7.