NASA's orbiting Chandra X-Ray Observatory snapped this shot of Stephan's Quintet, a group of five galaxies, four of which are currently in collision. Follow the link for a larger picture.
Link
Previously on Neatorama:
The Hand of God
Smiley Face Galaxy
You can look for signs of interaction - see that bright blue bumpy strip in the middle? that's star formation triggered by the interaction!
I do merger of galaxies for a living. any questions, please dont hesitate!