Created on request from the Bukkit forums.

This plugin executes commands on players periodically with a given probability. The example config.yml file should be self-explanatory:

#Commands can be declared here
#Every command must have the following keys:
#command: "<text>"   - The command to execute (without a /). Every {p} in this command will be replaced by a players name.
#mode: <number>   - The mode of the command. Can be either 1 or 2. In mode 1 the command will be executed by the console, in mode 2 the command will be executed by the player.
#delay: <number>   - The delay of the first execution of the command after a server (re)start, in seconds. Can be 0.
#time: <number>   - The time between command executions, in seconds. Must be 1 at least.
#probability: <number>   - The probability with which the command will be performed for each player. Must be between 0.0 and 1.0.

#Will give every player one diamond with a probability of 50 percent every minute.
consolecommand:
  command: "/give {p} diamond 1"
  mode: 1
  delay: 30
  time: 60
  probability: 0.5

#Will make every player kill himself with a probability of 10 percent every 15 minutes.
playercommand:
  command: "/kill"
  mode: 2
  delay: 900
  time: 900
  probability: 0.1

CommandRandomizer