In one of my classes last fall, a girl was texting pretty much non-stop. Finally, the instructor stopped the lecture and said "Miss XO, is my lecture disturbing you?"
She looked up and said "um, excuse me?"
The instructor told her she needed to decided whether to listen or text. But she couldn't do both.

My roommate said she was at a movie once that got boring, so she started reading the texts sent and received by the girl next to her.