Time Machine
In the touristy book shop at Union Station they regularly have Democrat and Republican gear in the window. Right now it's a t-shirt supporting Obama, and one supporting McCain. The problem is that the phrasing on the Obama shirt is bizarre. Under a picture of him it says

"Obama for President - Changing History."

At first glance, you may not notice a problem with that phrase. But then you think on it more. Do they mean "Making History"? Or is he actually a time-traveler? That could be handy in a presidential campaign.