Rather than spend a long time trying to describe this one, I'm going to give you two very different examples.
The first is a story I recently heard on Escape Pod called "The '76 Goldwater Dime", written by John Medaille and narrated by the always-excellent Norm Sherman. It's about a guy who collects coins. And what could be more ordinary than that? But these coins, boy, they certainly are not ordinary. I can't really say much more without giving it all away -- go and listen to the episode. Or, heck, you can even read it in its entirety (it isn't very long) at the link I provided above.
My second example isn't even a story. I read about it in a post on Jeff Vandermeer's blog. Some of his Finnish fans had created t-shirts and hockey jerseys for a fictional team called the Tallahassee Tentacles, named for Jeff's home town and the frequent occurrence of squid in his fiction. I'm Australian -- sport is a pretty ordinary, everyday part of my life. I really liked the way the Tallahassee Tentacles turned that on its head.
The trick, of course, is that nifty transformations like this don't make a complete story on their own. I think you could argue that "The '76 Goldwater Dime" would have functioned better as a piece of flash fiction, and although the Tallahassee Tentacles hint at a story, they aren't one yet.
Still, they're a great hook to drag people like me in.