Random map that simulates earth-like plate tectonics, geostrophic winds and rainfall. Also, this map has a high likelyhood of 'New World' type lands only reachable on the open ocean. For a more thorough description, see the thread below.
http://forums.civfanatics.com/showthread.php?t=310891
http://forums.civfanatics.com/showthread.php?t=310891