Actually there are three! There are scene modes, there's EXR auto mode, and there are also some Adv Auto things too. The Adv ones are panorama, pro focus and pro low light. (At least. That's all I see, so far.)
The sensor is able to sample some of its components in different ways. For example, I think in the pro low light mode it samples every other pixel, some of which are normally used to sense the same colors. But since they usually should show up as the same value, if ISO is high and they are not, it probably is noise, which can be gotten rid of. At least I think that's how it works.
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!