Thinks

HoloToy shifts perspective using (I assume) accelerometer information (rather than head/eye-tracking for perspective as seen on the DS and Android) giving a levelhead-like experience. Looks particularly good on the iPad. (via Games Alfresco)

Boxed AR

AR works particularly well when it is framed within something in the real world. This example developed by Dassault Systemes puts a game into a cereal box and uses tilting as the control mechanism. The little bits of AR that come out of the box are made more believable because the distinction between real and virtual has been blurred so well. Another excellent example is levelhead.

LevelHead is a simple (and also a little clever) interactive spatial-puzzle AR game where you guide (by tilting) a character through a maze of 6 interconnected rooms within a cube. Multiple cubes can be used with the character moving from cube to cube. According to Julian Oliver the code, which uses the ARToolkit and ARToolkitPlus, is going to be open sourced soon.