That’s a tough one really, it all depends on the person. For myself personally the ragingly dorky style I’d find cuter than anything, however if you don’t want to go that route then I’m stumped.
You could try this, you might find it dorky though… send an invitation similar to the acceptance letters in the movie stating:
you’re presence would be thoroughly enjoyed for the viewing of:
Should you like to be my date for this momentous occasion please respond with your owl asap to:
Or something like that really… it’s a little dorky but it’s creative. If you can try and make the letter yourself.