I have heard both repetitive and repetitious used in everyday speech to describe something that repeats, and I'm wondering what the real difference between the words is. Does one have a different connotation than the other? Do they describe different things?
I would say repetitious is a more 'broad-reaching' term.
A relatively small amount of repetition concentrated in a single context can be repetitive.
If something repeats itself enough to say that it does so characteristically in various contexts, it becomes repetitious (repetitive repetition, if you will).
Having said that, I don't much like repetitious. I think it's a nerdy word.