I have actually had a ball playing some of these guys for weeks on end, creating my own imaginary circumstances which prevent me from compliance with their requests, but always with the promise of a golden crumb just waiting around the corner. It's fun to see how just how outlandish a story you can create before they realize they're the ones being scammed. Believe me, these guy's are DUMB. It's also a nice touch to 'cc' the FBI and/or INTERPOL on your final response.
I agree with the above sentiment..
Fight fire with fire!