Sophomore year I was sleeping over Kleppy's for the weekend and had packed a bag. I had a vibrating toothbrush. In the morning I had animal classes and we all could tell something was vibrating, but no one knew what it was. We realized it wasn't anyone's cell phones. Our gazes snuck to my bag, where they stayed.
There were endless jokes on the supplies I kept in my backpack.
I eventually opened it up to find that it was my electric toothbrush. I had totally forgot I had packed it.
I was laughing all day. It went off a few times but I didn't bother taking out the batteries. It was worth the laugh having my bag vibrate randomly between and during classes.