Bingo (anecdata)... a few years ago I spent the last 15min of a flight into SFO talking to a lady (who had been playing Bejeweled for 4 hours straight) about us

Bingo (anecdata)... a few years ago I spent the last 15min of a flight into SFO talking to a lady (who had been playing Bejeweled for 4 hours straight) about using touchscreens so long (it's my job). She mentioned how shaky she gets when she has to stop playing... I asked what she did... a game designer at Zynga.