Here are a few plugins.. Just download the dlls into the plugin directory of the server.

Message: An almost exact replica of the Med Board.
commands: read / read # / post suject,message / take #


Darknomads: This is exactly like the darknomads.dll from darknomads.com. it just incorporates its features into the chat server.
Commands: Clantown searchphrase / riddle searchphrase / combs searchphrase

Aol Instant messenger:This plugin allows users to add their AIM screen names to a database. An admin user can then send a notification to all users. The notifications can be generic or specified in the command.
Commands: Aimadd screenname / Aimlist / Aimnotify message

Battleship: The classic BATTLESHIP!!!.
Commands: Use BSHelp command once the plugin is loaded. Too much to explain here.

Telnet:This Plugin allows people without Mud-Master or Zchat to connect to the chat server using nothing but telnet.
Commands: .setn name / .chat command

Examples:This zip file contains a template with lots of details on how to write plugins. It also includes the FULL source of the message, battleship, and telnet plugins.