Zero collision responsiveness - C#

This has been freaking me out for the past two days and I know it's something fundamental I've gone and forgotten: None of my collision functions are responding when objects collide. They just don't seem to be getting called. Neither onTriggerEnter, onCollisionEnter or onColliderEnter.

I tried using them in a project I'd been working on, then switched to a completely empty project and started with just a pair of cubes. I've done things as per spec in the tutorial I was following, gone along with the instructions posted in answers to questions like mine and I've got RigidBodies on everything (originally only as many as required by tut), colliders on everything and triggers on everything.

The boxes go into each other and nothing comes up on the console.

URGH, what am I doing wrong? This is driving me nuts X(

The following code is included in every collidable object, each of which also has a rigidbody, collider and isTrigger because at this point I'm just flailing about.

 void onTriggerEnter(){
     Debug.Log (string.Format("WORK DAMMIT"));
 }
         
 void onCollisionEnter(Collision obj){
     Debug.Log (string.Format("WORK DAMMIT"));
 }
         
 void onColliderEnter(Collider obj){
     Debug.Log (string.Format("WORK DAMMIT"));
 }