Dutch juggling conventions can be found on:
Juggling Edge www.jugglingedge.com/events.php
Jongleer.net www.jongleer.net , there is also more information about juggling in the Netherlands on Jongleer.net .
If you want to subscribe to these calendars (ie automatically have Dutch juggling conventions added to your own on-line calendar) you can click on the button at the bottom right of the calendar.
It is also possible to just add individual events to your calendar, click on the event and then click on the "copy to my calendar" link.