Do what The LED Museum does, connect it's input to a solar cell and check for PWM on LED lights. You could also use it check waveforms on driver circuits, things like that.
Have you had any problems with the selector on your 87? Mine seems to have dirty contacts, depending on how i set it in the drawer it sill sometimes turn itself on and off and kill the battery in a few days.
This gives me some ideas to use my scope for, it's been collecting dust for a while now.