Here is an illustration for the book Secrets of Popular Culture, drawn in early 2007. Cast your mind back to those days. One of the big stories was about a practice called 'extraordinary rendition'.
Still don't know if 'sick' is youth slang for 'really good' anywhere outside Australia and New Zealand; not game to go to urban dictionary dot com to find out! It's one of those opposite things, like 'bad', 'wicked' or 'the s--t', all of which mean good, in the right context. At the time when this cartoon was drawn, I wondered if the use of 'gay' as a perjorative by the same age group sprang from their same ironic wordplay as 'sick'.
Later on there was a whole South Park episode about the same topic! They've tackled that topic a few times, actually. In two minds about South Park. Used to think it was fully sick, but now think it's fully sick. The next cartoon, which is in Test Your English, has a similar idea to the last one.