In acknowledgment of gay rights, Google has added an assortment of colors between the organic and sponsored results as seen below:
This was first spotted by PingPongPie, but it looks like there's a lot of momentum given this implementation. My thought is that it has to do with Google being located in California and gay marriage finally becoming legalized, but I really don't know. It's just a guess.
Interestingly enough, as per a Sphinn thread, it's only visible in some states. One member who resides in South Carolina isn't seeing it. I'm in New York; the screenshot above is mine -- I see it without a problem.