Something that you find awesome in an incredibly nerdy way. Often used by closet nerds when discussing nerdy things away from their non-nerd friends.
Is not exactly an insult, but its use usually involves the users making fun of themselves to some degree.
"man...you should see the new Space Marine codex...its totally nerdtacular!"
when something is so nerdy, that it suddenly becomes popular, usually with those really annoying girls ages 10-15 who have no real opinions and just say they like what ever is "cool" at the moment.
teeny bopper kid #1: (in 2005) oh my gosh! those glasses are soooo nerdy,why would anyone wear them?
teeny bopper kid#2: (2005) i know right! ick.
teeny bopper kid #1 (2012) those (same) glasses are so nerdtacular!
teeny bopper kid #2 ikr!?! i already hav a pair! totes amaze!