This is a series of Nuke BlinkScript experiments i did last year.
Based on the alpha of the input layer (in this case the text), it will spawn particles.
In some of the tests the particles are only spawned upon collision with the text layer, and as they collide their velocity is affected based on the thickness of the layer.
Special thanks to:
CadereSounds - freesound.org/people/CadereSounds/
draganov89 - freesound.org/people/draganov89/
ERH - freesound.org/people/ERH/