This might already be posted in here somewhere, but in case it's not, I thought this test was interesting. It tries to determine your socionics type using Reinin Dichotomies. It said I was Intuitive Logical Extrovert which is a type I never would have thought myself being. It might be helpful for determining which quadra you're in at least.
http://www.helloquizzy.com/tests/the-socionics-test-1