RPG Registry
   Huge database of role-playing Conventions, players, and games - both online and offline.
   http://www.rpgregistry.com

RPGA Convention Calendar
   Webpage goes to current month of official RPGA activities in the United States.
   https://events.wizards.com/RPGAWeb/external/calendar.asp

Rocky Mountain Benefit Gamers Association
   Raises money for small, local charities in the Rocky Mountain region, typically by holding various events throughout the year, many of which are gaming (like board games and role-playing games, not gambling) related.
   http://bengames.org/

Steve Jackson Games - Convention and Trade Show Schedule
   Listing of events submitted to Steve Jackson's list, from all over the world.
   http://www.sjgames.com/con/index.html

The SF Site: Conventions
   Science-Fiction gaming convention calendar.
   http://www.sfsite.com/depts/cons01.htm

UK RPG Convention Calendar
   Upcoming roleplaying games conventions in the British Isles. Looks comprehensive and informative.
   http://www.philm.demon.co.uk/RPGs/conventions.htm