Hello, CivicSpace Labs is currently maintaining or distributing a large number of event management related modules. We are interested in collaborating with others to develop some common APIs for event management. We have categorized the modules into invite, register, search, attend, and follow-up tasks. http://drupal.org/node/50287 If we are missing some event management modules or missing specific features please contact me to update the chart. Cheers, Kieran