EE2 - Direct output from plugin

Noob question here:

I need to be able to output KML, ICS and JSON data on-the-fly (for some front-end javascript) from a plugin or extension. Is there a way to do this that will allow me to bypass templates?

In other words, is there a way I can hook into the system and pre-define a uri to get such outputs from my plugin/extension?

I just want to simplify the process of installing these things in the future.

Is such a thing allowed?

If so, I could greatly use an example or two.

Thanks!