Somewhere between 150 and 250 light years from our galaxy exists a fascinating phenomenon known as "the Great Attractor". Sadly, however, there isn't much to tell about it, for we still don't know much about it.
Map of our local super clusters
It turns out that our galaxy, along with several local galaxy clusters, are all accelerating towards some central point in the direction of the constellations Hydra and Centaurus which has been dubbed "the Great Attractor" at about 600 km/s. The mass necessary for such a pull would have to be something on the order of 10s to 1000s of milky way galaxies, or ~1016 solar masses. As massive as this anomaly would have to be, you'd think we'd know more about it, but it happens to be past the Zone of Avoidance, an area that is obscured by the Milky Way galaxy. From what we can see, it looks like most of the mass of the Great Attractor is found in a cluster of galaxies called Abell 3627. The relatively recent Clusters in the Zone of Avoidance (CIZA) project suggests that the Great Attractor is only 1/10 of the mass pulling us.