Question: What is the most unusual object that's ever been found in space?

Hugh Osborn answered on 21 Nov 2014:

One of the most interesting I can remember is Hanny’s Voorwerpje. This was a strange green splodge floating in the middle of space, millions of lightyears from a galaxy. Eventually it was shown to be a cloud of hydrogen emanating from a distant galaxy and refracted by the gas and into our telescopes.

The coolest thing about that discovery is that it was not made by an astronomer at all. Instead, a school teacher named Hanny was browsing images on Galaxy Zoo (an online game where the public help identify galaxies for astronomers) and found the bizarre cloud that has since been named after her! Pretty cool, eh?