The demo's purpose is to demonstrate the power of SPARQL against distributed data sources on the web. In this case, the data sources are calendar files using the iCal standard. Google Calendar is excellent, but it's query abilities are very limited (date ranges and text). If you are fluent in SPARQL you'll find out that you can begin querying for just locations, organizers, etc. The "Query" tab is for you to enter a SPARQL query against the selected calendars in the "Calendars" tab. In SPARQL lingo, all calendars are added as named graphs. The "Search" tab is for those of you signed into Google Calendar and would like to discover "new" calendars through text search. Then you can add the newly found calendars to the "Calendars" tab and execute new searches against them.

NOTE: This has only been tested in Firefox. You must enable UniversalBrowserRead for it to work.

If you get a 400 error. It means that a parameter to the query was incorrect. It could be one of many things:

• The calendar you've selected is not publicly available.
• The iCal to RDF service failed to parse the iCalendar.
• There are no calendars selected in the Calendars tab.
• I dunno.