I love the little "did you know" gadget on my sidebar. The one for today was "There are about 20 English words with no perfect rhyme, including "orange," "bulb" and "film."
I never gave it much thought, even as a writer since I rarely write poetry, but that would make things tough. What if you had to come up with something for "orange" for instance? Do you force it, using something like "flange"? and how do you work flange into a sentence that has anything to do with the fruit or color? Funny stuff. That there would even be words that no other word rhymes with is just amazing when you think about how many words there are in the English language.