I just got my n800 the other day, but I ran across the same thing that tz1 mentioned: I've got a button on my bluetooth headset (Moto H680) that doesn't do anything.

I coded up the idea mentioned here - bind the button_press event to a script that runs xte. The built-in media player needs a carriage return to play/pause, but you could modify this to do just about anything.

I posted the python code here along with an archive containing the latest sources for XAutomation with compiled binaries. Or, if you prefer, a second post with just the files executables.