I like concepts that are put together, and don't go together. A lot of the fiction writing that I work on involves putting characters together that you couldn't imagine being together in any sort of logical fashion.
Here are a couple of "Hello Kitty" related concepts that don't go together, but are funny:
Hello Cthulhu (for you H.P. Lovecraft fans, unless you're the ones who take the Necronomicon seriously. This concept has been used by more than one artistic soul--one of them, not the one that did the cartoon to my knowledge, has a cafe-press store of Hello Cthulhu stuff. I think I need the coffee mug.)
Hello Kali --as a Kali worshipper, I find the rewritten mantra hilarious. And I don't think Maa takes offense...