The pentagon module (108 degrees)

Introduction -- Making the Modules -- Making the Polyhedra -- Jim's Origami Page
Start with a 4x3 piece of paper, and fold like an accordian into three segments:

Fold the lower left and upper right corners in. Use only the top layers. Unfold:

Valley fold along the dotted line, and unfold:

Re-fold the corners, this time folding all layers:

The final piece: