Sparql query:

{{#ask:
  [[Category:Occurrence]]
  [[StartDate::>Oct 01 2012]]
  |? StartDate
  |format=calendar
}}

	StartDate
Demo PSMW meeting call 2012 12 14	17 December 2012 21:00:00
Demo PSMW meeting call 2012 12 19	19 December 2012 13:30:00