BukkitInsider

BukkitInsider: inspect events and plugins. On the fly.
Version: 1.4

This quick, small and dirty plugin is able to get all event subscriptions and list them to you. Also, of particular interest is the ability to calculate average time to process a certain event.

Some technical details: it works partly because of some black magic called Reflections. I substitute Bukkit's own PluginManager with my own that is very similar to the original, but allows me to intercept all events prior to another plugins and pull out my millisecond-precise stopwatch. Please note that this may add a few nanoseconds to the bill.
As you might know, black magic doesn't like to cooperate, so if you have any other plugin that does its own sacred rituals, be aware of possible bad interaction.

Screenshot:

Commands:

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• introspect - dumps information about event hooks into console. You can call it from chat though, but you won't get any output. Requires you to be an Op. Amount of imformation is just huge, you just won't see everything in that tiny Minecraft chat.