I too have had a recent string of flats. Nearly EVERY commute in the last 2 weeks...so roughly 6..??? (I don't ride everyday)
I always leave my bike in my classroom, and when I start to head home....flat.

It's almost as if some kid sneaks in and uses a stapler in my tire, then pulls the staple and runs.
I hope that is just my imagination running wild, but it is so frustrating that I have decided to keep my bike in my storage room as opposed to my classroom.