How do you get a geek excited? You combine two of their favorite things, such as the iPhone and the Sega Dreamcast. Sure, these two objects of nerd lust have no reason to go together, but who cares? The point isn't to be practical. It's to do it for the sake of doing it.
Here you see the Dreamcast controller iPhone dock. There's no real benefit to plugging your iPhone into a gutted controller other than getting to look at said controller a lot more often, which may be all the reward you need.