Giggity

Giggity loads xcal/Pentabarf/frab XML files (that contain schedules of conferences/festivals/other events) and lets you browse them in various convenient formats.

Preseeded with many events including FOSDEM, CCC, FrOSCon, etc.

Giggity lets you organise your visit - select talks to be reminded of (with warnings in case of conflicts) or hide the topics you're less interested in.
Schedules are shown in whatever format you like - block schedules, plain timetables, or a clear now-and-next screen on the day itself.