I've read on an electronic device in a lot of the same scenarios as others;
dentist'schair
in labor (for both babies, I flipped between a contraction timer and a book on my smartphone until it was clearly go-time for the hospital. I think my MIL thought I was crazy)
waiting at amusement parks
while nursing (I do this all the time - keeps me sane in the wee hours)
on my honeymoon, in the London Underground during a blackout/stop
while cooking Thanksgiving dinner - gotta let the bird rest and everything else is in progress at that point
Pretty much anywhere I can reach and push a button or touch a screen I've read on some device.