These online tools provide visually interesting AS-related maps:
Graphical AS Matrix:
http://www.netlantis.org/index.html?menu=2&page=sagm
Graphical AS Path:
http://www.netlantis.org/index.php?menu=2&page=gasp
Jasvpi (Java Autonomous System Path visualization):
http://lab.verat.net/Jaspvi/