The "Criminal Minds" team heads to Gotham.
Think about it. Garcia and Oracle would totally make bestest cyber-buds, Reid and Tim Drake could work together to solve a mystery, Morgan and Nightwing would go out and kick ass together, and Hotch and Bruce can have a chin-measuring competition. And of course, depending on which season you set it in, either Gideon or Rossi would sit down with Alfred and have an incredibly interesting and illuminating conversation about Batman's psychology. (Still not sure who Greenaway would work with. Maybe Huntress? It seems like a good fit...) J.J., of course, would be working with Commissioner Gordon. (Supposedly, the writers of "Criminal Minds" structured the entire thing as a metaphor for the Knights of the Round Table. I think that the Batman mythos are an even better fit, though.)
And naturally, they'd be up against a whole freaking Rogues Gallery of Batman's foes. (The comment that inspired it all came from my lovely wife, who pictured Gideon describing the Joker from 'The Dark Knight' as "an organized serial killer whose M.O. is pretending to be disorganized.") The Riddler, the Mad Hatter, Zsasz, Scarecrow...seriously, why is someone not making this right now?
Who am I kidding, I'm saying this on the Internet. I could probably get twenty thousand hits searching for the fanfiction alone.