I am loving this simple but really playable iPhod Touch/iPhone game called Boxed In. It is free, has about 100 levels and (at level 25) has yet to get dull. You are a small robot whose aim in life is to collect cogs and get to a goal. The maze is scattered with boxes that you can push about (but not pull). There are also colour coded blocks that will disappear when an object (a box) is pushed into the corresponding coloured square area.