The Dude network monitor: Here’s a handy replacement for Ipswitch’s old Ping Pack Pro. It will ping the crap out of your subnet and tell you what responds. Handy for finding devices that may have DHCPed themselves into oblivion.
[…] automatically scan all devices within specified subnets, draw and layout a map of your networks, monitor services of your devices and alert you in case some service has problems.
As near as I can tell, this utility was named for Jeff Bridges character in The Big Lebowski.