The question was imagined after a co-worker was complaining for an hour about some guy who could not answer basic Java questions on an interview after self-identifying himself as "8 out of 10" on Java.

While that was an obvious fib, I personally always had major trouble defining my specific language skills on a sliding scale unless I'm given specific guidelines (remember >40 standard libraries by heart? Able to solve 10 random Project Euler problems in <30 mins each? Can write implementation of A, B and C data-structures from scratch in 30 mins? Know 30% of standard? Can answer 50% of questions on StackOverflow pertaining to the language?)

So, I was wondering - is there some sort of commonly accepted methodology for translating such tangible benchmarks into "rate yourself on a language between 1-10"?

"Kernighan gets an A, God gets a B, everyone else gets C and less" type jokes are not helpful :)