We have written a Java applet to illustrate the meaning of curved geometry. The applet provides a mapping interface similar to MapQuest or Google Maps; features include the ability to navigate through a space and place permanent point objects and/or shapes at arbitrary positions. The underlying two-dimensional space has a constant, positive curvature, which causes the apparent paths and shapes of the objects in the map to appear distorted in ways that change as you view them from different relative angles and distances.
Felder, Gary and Erickson, Stephanie, "CurvedLand: An Applet For Illustrating Curved Geometry Without Embedding" (2010). Physics: Faculty Publications. 4.