Below are some resources related to the galaxies beyond the Milky Way:
- The Fermi Gamma-ray Space Telescope has produced an "Active Galaxy Education Unit."
- The Galaxy Evolution Explorer (that is, GALEX) has a few activities for teachers.
- You and your students can contribute to a project to classify galaxies from the Sloan Digital Sky Survey with Galaxy Zoo. This has been incorporated into a newer resource from the SDSS team called Voyages, and there is a Voyages activity on galaxy shapes.
- Phil Plait's Crash Course Astronomy has "Galaxies, Part 1" and "Galaxies, Part 2".