Comet 17P Holmes brightened from an extremely dim 17th magnitude object to an easily viewed, naked-eye "star" even visible in light-polluted cities, due to some poorly-understood explosion in the last two weeks. In binoculars, it's clearly not a star but a white sphere. From what I've read elsewhere, these brightening events have occurred before, but never so dramatically as this one.
It's also ridiculously easy to spot. Find the Cassiopeia constellation in the northeast sky around 9 p.m., look a short distance down and to the right to find another star, Alcheb, about as bright as the Cassiopeia stars. Alcheb appears to form the apex of a small, narrow triangle, and Holmes is the star at the bottom left.
Holmes is moving though, so in a week or so these directions will be less clear, and the exploding debris might dissipate and go away. If you're going to look, do it now.