My friend Amanda sent me this story:

So, I just bought a bike from Target yesterday.  I was outside on my front lawn fixing it, because some idiot assembled it wrong.  These new neighbours were moving in, and I told them I'd watch their stuff while they go to and from their apartment.  My bike is sitting up on a hill, and I'm about 50 feet away.  I look up and see some guy taking off down the hill with it.  "OH FUCK," I say, "that's my bike!"  Not even thinking, I take off sprinting after him, which is amusing since I'm a smoker with bad ankles who was never able to run even in my youth.  I managed to keep up with him, and see him dart into the Metro station.  At this point, I run into my friends Jessica and Mark, and tell them what happened.  We cross the street, kind of darting in through traffic, hurdle the turnstile, and get up to the platform just as a train arrives.  I see the guy with my bike going into the last car, and I immediately press the emergency button and tell the conductor what happened.  A security person meets us, and I tell him what happened.  At this point, they've alerted the Metro police, and the security guard takes Mark and me up to the guy, and asks said thief, "Is this your bike?"  The guy pauses, and says, "uh...no.  it was just sitting here."  I take the bike back and ask him really sarcastically, "oh, I don't suppose you've seen a set of keys that were also 'just sitting here', have you?"  At this point, the cops come and take the guy off the train, and question him and question me.  Then comes the shitty part.  Since we crossed statelines during the chase on the train, and my pressing charges would only result in a misdemeanor, and would be fairly fruitless.  At this point, I was happy enough to have my bike back, and really tired from my adreneline-induced sprinting and chasing after thieves, so I didn't press any charges, and went home.  My keys were on the ground right by where my bike was, and everything turned out okay.  The weird thing is, I'm surprised that he was able to ride the thing in the first place, since the chain kept slipping off of the gears, which is what I was trying to fix.  Wow.  What a day.
 
-AmandaMM

If it was me, it would have turned out not to be my bike afterall. I remember my sister's bike getting stolen once when I was a kid. She went looking for him and kicked his ass around the block. I always thought that was so bad ass.