At ZendCon 2014 there will be a PGP Keysigning event. To participate all you need to do is a) have a PGP key you would like signed by other particpants and you will be able to sign other participant's keys with and b) have some form of official identification that matches the primary identity on your key. For example, if you name is listed on your PGP key as Bobby Tables you should have a government-issued ID that reads close to Bobby Tables. (Common substitutions like Matt for Matthew or Jen for Jennifer are usually acceptable.)
For some background and how-to information, check out my blog posts on a similiar PGP keysigning event at php[tek] 2014 and Signing PGP Keys for the mechanics of how to sign keys.
The web of trust is an important component to the security and usability of PGP keys for signing and encrypting. I am pers