For those that weren't able to make it, Sebastian Bergmann has posted a short summary of what went on at the Dutch PHP usergroup's TestFest 2008 event.
I arrived shortly after noon, just in time for the start of the test fest at 12:30. After a short introduction to PHPT, we started writing tests for the Reflection API. We managed to write 37 tests with 10 people in 4 hours.
You can find out more about the user group on their website including meeting times, locations and links to other great PHP resources.