In their interview this morning, someone asked Michael Andretti to talk about how the whole deal came about, and he said it was because they have the same agent/manager. He got Kurt and Michael together last year when Andretti Autosports were looking into starting a Cup team, and it sort of took off from there.
When asked about his desire to drive in the 500, Kurt professed his commitment to the Furniture Row team. When pressed further, he said that he would want to drive in an oval race before trying Indy to get used to racing in traffic, which makes the Auto Club prospect more interesting.
At the beginning of the interview, he said that today's test was about the biggest thrill he could imagine, "except maybe an F1 car." So maybe he want's to be the most versatile driver around. After all he did do the ride swap with some Aussie V8 Supercar guys down in Austin a few weeks ago.