Take the Archicad competency test. Whee.
I thought it was pretty tough. I managed an 86.
House rules: Since each question is timed (90 sec), I think open book/open Archicad is permitted. If you can open the Attach XREF dialog and figure it out in 90 seconds having never looked at it before, more power to you. The point is to learn anyway.
Unfortunately, they don't tell you which things you got wrong. You'll probably have a feeling though.