Aside: Yes, alternate nostril breathing

I kid you not.  Alternate nostril breathing.

You take your hand, put your second and third fingers on your "third eye" (I was so impressed that my dad knew where that was without further explanation -- that spot on your forehead between your eyes where folks of certain beliefs put a dot), leaving your thumb and fourth finger free to close up one or the other of your nostrils.

Now close your left nostril.  Exhale through your right.  Inhale through your right.  Close your right nostril and open your left.  Exhale through your left.  Inhale through your left.  Repeat.

There was some sort of importance to starting on the exhale, also some sort of importance to starting and ending on the right, neither of which she explained.  Class leader also said that this was really relaxing and a good cure for insomnia.  I don't doubt it.  You get all calm when you're focussed on your breathing like that.  Of course, I expect any sort of calm, repetitive thing which has you taking nice long relaxing breaths is equally good for insomnia -- with the added bonus that you don't look like an idiot closing off your nostrils.  But there you go.