'roofies' is the street name for rohypnol.
To say to a person that they have 'class' or 'charisma' with a capital C, or 'style' with a capital S, is to emphasize just how Stylish, full of Class or Charisma they are. Note also, "He's trouble with a capital T", which is not a compliment!
'class' is spelt with a 'c'. So, if you tell someone they have 'class with a capital K', you are actually saying the opposite - they don't have Class. It's like Klass is some Frankenstein's monster of a distortion of the word 'class' - and so is their style and manner compared to people who really do have Class!
GHB: take your pick:
What is GHB?
What is GHB? A modern rave party scene drug used to get high. Also used as a date rape drug. It can kill.
What is GHB? - 48k
BBC NEWS | Health | GHB: Unpredictable club drug
29 Jun 2003 ... GHB is widely known as a 'date rape' drug, but its most common use by far is in clubs, where it is raising serious concerns.
news.bbc.co.uk/2/hi/health/3029854.stm - 38k - Cached - Similar pages