Anyone have a solution for varying volumes on your HTPC?

I'm not using XBMC, Boxee or anything. Just windows 7 on a dedicated HTPC hdmi'd to a big screen. The issue I have is when watching YouTube videos where there's no volume compression like on Hulu. One clip might be quiet and the next will be ear shattering.

Is there any kind of application I can download to equalize volume across my entire system?