Note: If you try to submit a page of answers after missing one or more questions, a box will appear at the top of the page (...not the top of the screen...), meaning that the test will appear to freeze if you are at the bottom of the page of questions.
@Olga linked this on the WSS Facebook group. I thought it was rather good, and enjoyable too.
http://www.musicaluniverse.org/
Here are averages from the general population:
Extraversion: 4.44
Agreeableness: 5.23
Openness to Experience: 5.38
Conscientiousness: 5.40
Emotional Stability: 4.83