ScrubIT (filters pr0n, so probably not what you want): "ScrubIT offers clean, reliable, and speedy DNS service FREE of charge. Our filtered DNS scrubs out the bad stuff and is absolutely simple to setup and use. Try it today!"
* 22.214.171.124 * 126.96.36.199
OpenDNS (you'll get ads on DNS misses): "Taking a few minutes to unbundle your DNS service from your ISP's Internet connection means a safer, faster, smarter and more reliable Internet experience for everyone in your household."
* 188.8.131.52 * 184.108.40.206
vnsc-pri.sys.gtei.net (no idea who or what this is; but their DNS sure is open):
My computer is suddenly displaying an "antivirus" HTML document over the top of my desktop (it's blocking the wallpaper I made, but allowing the icons to show through). Properties reveals that this HTML thing is: C:\WINDOWS\desktop.