Some DNS servers - if you know your ISP's DNS servers are causing problems.  Perhaps useful as secondary/tertiary DNS servers?

208.67.222.222
208.67.220.220

Safer = OpenDNS can identify and stop sites trying to phish (steal) your personal information or money.
Faster = Huge DNS caches in Seattle, New Yor, washington DC, and Palo Alto
Smarter = .og becomes .org

The catch = OpenDNS makes money by serving clearly labeled advertisements on search results pages where we cannot resolve your intent (i.e., not a known typo).

System status page = http://208.67.219.60/
Home = http://www.opendns.com/
What we do = http://www.opendns.com/what/
FAQ = http://www.opendns.com/faq/