These days, if you don't spend your idle time wondering what would happen if two completely different fandoms crossed over to the other side, you're the weirdo.
Maybe the most obvious crossover that doesn't involve "what if __ and __ kissed?" is, what if Disney characters went to Hogwarts?
What houses would they be sorted into?
What cliques would form?
How short would Belle's skirt be?
Exactly how hunky would Flynn look in sweater and tie?
What would Aurora do if Maleficent was the new DADA teacher?
What would happen if Snow gave one of the Dwarfs a sock?
Eira1893 (Annabella) on DeviantArt has most of those questions covered with her Disney at Hogwarts series, including who would be sorted into what house.
Those are just a few of the characters she's taken the time to crossover. Please visit her DeviantArt page to see a handful more.