Blue Skies
I am just going from memory here, so some items may be omitted.
1)Psych assessment personality questionaires, can't study for that, just answer the questions. Example... I like to kill puppies...agree or disagree.
2)Spatial and Memory tests. Change frequencies, altitudes, speeds, while looking for a flashing X. Testing memory while being distracted. Some questions similar to ATP question, regarding position of A/C in relation in to an NDB/VOR.
3)Some basic maths, nothing to complex, basic High School Stuff.
4)Some basic ATP Theory questions, some based on JAR OPS rules, again nothing to tricky.
5)Basic coordination exercise with Rudder and Joystick.
Most of the stuff you can't really prepare for, other than maybe doing some soduku or pattern type puzzles from the Saturday or Sunday paper. They give you a full explanation of how it all works beforehand, and you get a practise try before the recording starts. So relax, just be yourself.
There is a lot of info in this thread. Try to wade through the thousands of posts, and you'll get a pretty good idea what to expect.
Good Luck