I've seen people with number passwordsinstead of slide to unlock, and instead of normal app icons they have things like: http://img134.imageshack.us/img134/5366/072011091908ht6.png
Oh, and like this
http://photos-d.ak.facebook.com/photos-ak-sctm/v156/156/108/1458000355/n1458000355_30195459_9922.jpg