I guess all of you people "don't" really know what's Chuunibyou, in Japanese(same with Chinese) it means "8th grader syndrome".
Because we get to middle school after 6th grade, starting with 7th to 9th grade.
「中二病」the words are actually "Middle 2nd disease", why is it called Chuunibyou? I think it's because..........In 8th grade students are very delusional, creative and has the guts to act out, so that's why it's called Chuunibyou.
Here's a link of me being a chuunibyou (The person in brown)
http://www.youtube.com/watch?v=UBPi6o8fE_E
sorry for Chinese translation and my grammar.......