Back in the days when you could leave your car unlocked in the driveway, and you could leave your Unix shell account unlocked on your server, the term hacker was a noble one. We keep trying to reclaim it from the identity thieves and 1337 skryptkiddi3s, but language is notoriously hard to manage in any purposeful way. Still, we haven't created a suitable new term for the concept, so any references to hacking in this post refer to the good kind.
What hackers do best is use the tools at hand in ways that were never intended by the providers of these tools. Smart providers revel in this. Idiot providers do all they can to prevent it. In the interest of promoting the smart providers, I'd like you to take a look at the latest version of brilliant hacking.
Mobile phones are getting pretty sophisticated. A lot of them now have accelerometers in them -- something that can detect movement. Of course, almost any mobile phone has a vibrator (steady, now), and virtually all of them have a speaker. Add in the fact that these three things can be controlled via software. A good hacker will look at this situation and ponder, "What can we do with these raw materials?" Well, some boffins in Glasgow (there's no better hacker than a Scots hacker) came up with a doozy. (Go ahead, click on doozy. Go read about it. This is how the internets are supposed to work.)
I never would have thought to combine those features in this way, but it's exquisitely hawesome. (Wil Wheaton taught me to spell awesome this way. Honestly, it's not my fault.)