In a not-so-subtle jab at Windows, when you are browsing a local network with Leopard, Windows machines are displayed as a CRT monitor displaying the dreaded blue screen of death.

With Leopard, you can decide who's cool and who isn't.
Most developers expected the joke to be removed from the final version of Leopard. Anyone remember the winking Happy Mac of the OS 8 beta?
If you feel guilty making fun of Windows machines and their users you can use this how-to to change the default icon to something less hilarious.
Links:
[1] http://www.maclife.com/user/roberto_baldwin
[2] http://www.antipixel.com/blog/archives/2002/08/27/farewell_happy_mac.html
[3] http://www.engadget.com/2007/10/30/mini-how-to-remove-the-windows-bsod-icon-in-leopard-make-os-x-a-little-less-smug/
[4] http://www.maclife.com/article/living_with_leopard
[5] http://www.maclife.com/article/fun_with_leopards_screen_sharing
[6] http://www.maclife.com/article/apple_posts_leopard_guided_tour