AFAIK (I've been doing some reading on Ruby last couple of weeks) in Ruby everything (well, everything you can store or pass around; classes, literal strings, numbers, symbols, code blocks etc. etc.) really is an object.

100% OO is something else, though. You still have some operators that aren't method calls, but not many; iterators like each and math ops like + and <=> etc. are just method calls in Ruby.