Wierd problem with lights

[sublettm]

As I was driving home from work tonight I noticed that my headlights kept getting bright and then going back to normal illumination. My dash lights and the light for my radio was also getting brighter then dimmer. It had nothing to do with hitting the accelerator or backing off of it. I tried this thinking that maybe it had something to do with the alternator turning faster, thus generating more power, making my lights brighter, but that wasn't it. Just curious to see if any of you have had this problem and what you may have done to remedy this little bug. It really isn't that big of a deal except that the person in front of me probably thought that I was flashing my lights at him wanting him to go faster.

mike