So i see a couple more interesting things.
From the manual:
A control signal connected to this input will modulate the pulse width of the Square or Narrow Pulse waveform selected by Oscillator 1. Pulse Width Modulation (PWM) varies the duty cycle, or pulse width of a wave, and thereby changes its harmonic content. Among other things, PWM is often used to mimic the sound of ensembled strings and to thicken bass sounds.
LIN FM IN
Connecting an audio signal or high-frequency control signal to this input introduces Linear Frequency Modulation (FM) to Oscillator 2, which can be used to create brash, metallic, or bell-like tones.
I think that robot vocal looped thing i mentioned above – #23 Promobot IR77 – could be using the PWM IN with some sort of modulation – not sure. Would be fun modulating this input anyways.