In addition to localisation, I'm also adding some last bits to the site - "de puntjes op het i"
Twitter: The site uses the twitter module to import tweets. So all it needs is adding a the existing twitter account to a user, or better just making a new user 'twitter'. The latest tweets will be displayed in a block in the left sidebar, so I'm making a block and page for all tweets in views. I encountered two problems: First, quite counter-intuatively, the twitter module version 6.x-3 requires the 6.x-2 version of the oath module. Admittedly, it says in the description, but since I don't have access to the modules directory, it requires somebody else to do the changes. The second problem seems to be a bug: as site admin I was trying to add twitter accounts to other users, but while I was adding them from the specific users page ( > edit > twitter accounts), the account got added to my own account. I had to log in as the specific user to add it correctly. It's reported as a bug as http://drupal.org/node/1061030.
Calendar: A calendar block was set up, but showed also pages that were published. I've changed that to filter on node type so that it only shows events but then I noticed that the node type "event" didn't have a date field. I've enabled "date" to get a CCK date field and added it to the content type event. What needs checking now in which format the dates should be displayed, and whether it needs a timezone conversion.