The "Yet Another extended Hu¨ckel Molecular Orbital Package" (YAeHMOP) has been merged with the Avogadro open-source molecular editor and visualizer. It is now possible to perform YAeHMOP calculations directly from the Avogadro graphical user interface for materials that are periodic in one, two, or three dimensions, and to visualize band structures, total and projected density of states, and crystal orbital overlap/ Hamilton populations (COOPs/COHPs). Calculations on graphite, silicon, sodium, and a one-dimensional hydrogen chain are provided to illustrate the functionality. Similar exercises have been carried out in an upper-level undergraduate quantum theory course.