If I were to sit and list 'em all, you'd all think I was a complete basketcase. However, 99% of mine aren't things the average person would notice (I don't think).
However, I am surprised occasionally. My wife and I were sitting in our living room just talking, and I was sitting on the couch with the feet up on the coffee table. She noticed that my toes were moving back and forth rapidly and asked me what I was doing. I told her I was just tapping out the music on the radio. "But the toes on each foot are moving differently", she said. So I had to explain that one foot was tapping normal time, while the other was tapping double-time. (She just smirked and jokingly said "You're weird.")

you must be a musician or at least have real musical talent, by dint of your multitasking without even thinking about it. you could be a drummer or organist, for example. i wish i had that talent.