I just read a news letter from OpenDNS in which they state that they are now offering a paid solution where you get granular control of blocked sites.  Basically this mean that you can allow yourself (or equally important persons 😉 to bypass all the site blocking your site otherwize uses..  That seem quite clever..

Sitation from the newsletter;
A lightweight and innovative approach to per-user access controls, OpenDNS Web content filtering empowers you to grant individuals on your network permission to bypass blocked pages. No appliance. No software. It works efficiently through the cloud.