Bukkit

Adds a basic gang feature

Adds casino roulette to your server

Advanced muting plugin

Shoots command when someone votes, uses Votifier

Simple mine management plugin

Lets you flatten land

Adds signs which allows users to buy commands.

Gives money over time to PEX groups

CheckID

Adds a vote to stop raining

Makes it so all armors have the same damage reduction.

Casually stops players from writing with Caps-Lock toggled.

Kicks player who damage a specified mob

Lets players control their chat and player visibility

An easy-to-use potion protection plugin.

Speedball and paintball plugin

Extensive localization module

Logs all ips which connected to the server, and has a command to check duplicates

HousePoints

Adds a "heaven" concept where people have to wait there for a time until their next respawn