There's a brand new episode of "Funky Electrical Problems From Your 2011 Chevy Colorado" that aired this morning.
Driving in to work, I had no turn signals at all indicated on the dash. No aural indications of the lights switching on and off, either.
I parked my truck and turned the key to the "off" position, and nothing happened. The truck kept running and everything stayed on. I cycled the key to "on" and then back to "off". Worked normally.
At lunch I went out to check to see if anything was actually happening with the lights on the outside. Turned hazards on, all four corners lit up properly.
Switched on left turn signal, left side lights flash.
Switched on right turn signal, left sight lights flash...
Likely have a sticky contact somewhere in the switch. Possibly in the ignition switch as well? At least I have a project for the weekend though