It really is facinating! The one I took several years ago was the Kiersey test. You can take it at
Kiersey Temperment Sorter. It gives you the same results as the Meyers Briggs...a set of 4 letter indicators. A great book that goes more in depth (I JUST ordered it!!) is called Please Understand Me. I paid the extra $10 to get the full description online, but I'm interested in learning more. The test and basic results are free, or were when I took it several years ago.
Another test I haven't actually had the time to try yet, I found listed under a posters sig line. It's called an Ennegram. I actually found two websites with information and tests.
RHETI Enneagram Institute Free Enneagram Test Then we just took a personality test in my leadership class called the Matrixx. Our whole class did it and it was VERY accurate. Unfortunatly, I don't think they do it online, you have to find someone that has taken their course to give you the test (usually school counselors since it was designed for schools, initially). It's very quick and easy, but they just won't ship out the cards without having attended their course. If you want to check it out it's at
National Curriculum & Training Inst. They also have card sets for teenagers and grade school kids.
The final one I have been told about is something to do with what "animal" you are. I remember taking it once, but I can't remember where. I did a search, though, and found several! You might just try that.
Also, if you just do a search for online free personality test, you'll probably find a ton of fun ones! It's just that the above ones were recommended to me by professionals. I'm not sure about the others validity.
Have fun!