Hosting git repositories -- Gitolite allows you to setup git hosting on a central server, with very fine-grained access control and many (many!) more powerful features.

Traewelling-inspired journey logger with realtime data

Irssi smart filter to selectively hide JOIN/QUIT in busy channels

Order pizza over the commandline (circa 2004)

Extension for monitoring the ISC DHCP server with SNMP

Miscellaneous Nagios plugins and helpers

Vyatta config/op code for IPv6 router advertisements