The Redistricting Game
The Redistricting Game, put together by USC, is a tremendous amount of fun. You get the opportunity to be a partisan hack gerrymandering districts to your party's advantage. I played through the whole sequence. I remember being really disappointed when California voters rejected nonpartisan redistricting; the concept seems like it should be a no-brainer to me.
My one caveat is that I'm not really convinced that geographic compactness should be placed at such a high priority over more conceptual cohesiveness. What I mean is that it should be more important for district boundaries to follow well-established regional boundaries than for the districts to be shaped roughly like a square. Regions may follow coastlines, narrow valleys, railroads, highways, rivers, or other linear features, and if that is the case, then a congressional district following such a shape should not be tagged for violating geographic compactness.
There's a fine line, of course, between following a linear feature and gerrymandering to insure a safe seat for an incumbent party. A district following the narrow coastline of Santa Barbara, for example, would be perfectly reasonable, but the tortuous lengths to which the actual districts in California stretch themselves in order to capture areas of similar demographics is inexcusable.