I'll let the author of the photo explain it. You can find this entry on the Flickr page itself, by clicking on the photograph.
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It is a "hack" (prank) for the start of the academic year at MIT. New student orientation begins this week. The MIT website has a gallery of hacks from over the years: hacks.mit.edu "The word hack at MIT usually refers to a clever, benign, and "ethical" prank or practical joke, which is both challenging for the perpetrators and amusing to the MIT community (and sometimes even the rest of the world!). Note that this has nothing to do with computer (or phone) hacking (which we call "cracking")."
Interesting. So they have a different definition of "hacking" at MIT. And someone photoshopped a Tardis onto the roof. Cute but nothing to write home about. If they actually built a Tardis and made it dematerialise, then I'd be impressed.