Since McCain is beating the Ayers drum again, I think it's worth going into the details. Obama and Ayers met when they were serving on the board of the Chicago Annenberg Challenge, an educational foundation that was funded largely by the Annenberg Foundation (hence the name), whose chair is Leonore Annenberg, whose endorsement John McCain is bragging about.
If Ayers is a terrorist, then Annenberg (and her late husband) gave material support to a terrorist, and McCain should be attacking her for that, not praising her judgment. But Ayers isn't a terrorist, he's just another ego-ridden baby boomer looking back at his youth with rose-colored glasses. And I can understand that. I did some stupid shit when I was in my early twenties, and I've been known to play the "I learned a lot" card when I'm feeling nostalgic. Of course, I didn't blow anything up. At least, not that I can think of off the top of my head.