For anyone with an android phone (but I know there is an iPod version) LogoQuiz is a great way to kill time and see what brands have been retained in your conscious and subconscious!
Sometimes you will recognise the logo but you simply can't find the name! That brand hasn't connected with you, you haven't engaged with it on a practical or emotional sense. You may have seen it fleetingly on print, billboard, online or TV advertising where you have simply retained it's image but not its meaning.
Give it a run, see how you go. Really great way to score a few logo's between classes or on the train or bus!