What rhymes with car?

Adam has been learning about rhyming words. Well, kind of. He doesn't really get it, but he likes to try. So we were playing a little game where I say a word & he tries to say a word that rhymes. I said "car" and he said "light house." Okay, not quite. So then I said "fun" he said something else random that didn't rhyme. I explained that it had to be a word that had the "un" sound like fun. His response... "oh, like unexplainable?" Um yes, my little three year old, like unexplainable. He doesn't totally get the rhyming concept, but he's got quite a little vocabulary for a three year old!