How many angles can dance on the head of pen?
Infinite, you can create an angle in any direction. If you meant angels then none because god does not exist.
Replying to this, yes, I corrected the misspelling of angels, before I posted question. My question to you is who are you to say that GOD doesn't exist?
What is the trick behind the pen riddle where someone holds a pen different ways and says 'if this is a pen and this is a pen and this is a pen' then is this a pen?
depends what you want to learn, there are lots. you should learn the thumbaround first, many learn that first. you just place a pen betweenindex and thumb and put your middle finger on the body of the pen. then flick your middle finger and catch with you pen in between your index and middle, the pen should point in the same direction when you start and catch.