The last few days I spent some time hacking on our Drupal+Pentabarf mixture that powers fosdem.org. When you go to an "event" page (which is actually a session, a talk, a workshop), you can now see a list of other events that take place at the same time, e.g. here (under the "Other events at the same time:" header). Another useful feature is that the speaker and event pages from the schedule are also taken into account when you search for content, e.g. here is what you get when searching for "java".