A new announcement on the PHP.net site today talks about this year's TestFest, an even to help increase the code coverage of the tests on the PHP language itself.
During TestFest, PHP User Groups and individuals around the world organize local events where new tests are written and new contributors are introduced to PHP's testing suite. Last year was very successful with 887 tests submitted and a code coverage increase of 2.5%. This year we hope to do better.
The SVN repository and reporting tools are back again this year (a great improvement over years past) with the new additions of an automated test build environment and screencasts showing the tools in action. You can find out more about this year's event on the TestFest page of the PHP.net wiki (including finding an even near you to participate in).