PaulS:
When you define a main() function, the IDE doesn't add one. It's main() function calls init(). Yours does not. Significant? Quite possibly.
I'm coding inside of AtmelStudio, not the Arduino IDE, so there is a main() function. And my main() function does indeed call initializeInterrupt(), otherwise I would not be seeing any output from OC0A. So my timer is setup right cause it is running, but my ISR routine is not triggering. That's what I'm trying to get at here.