If you are on the look out for a new platform to develop software for then the latest, and perhaps strangest new possibility, is the Sifteo Cube - it promises to change the way we play computer games.
Each cube is a motion aware block with a full color screen and a wireless connection to a PC. Each block is about 1.5 inches and has sensors that let it detect its orientation and position relative to other blocks. The user can interact with a block by shaking it, rotating it or moving it and the top screen can be clicked.
Their ability to detect when they are alongside another block, they don't have to be touching, makes it possible to build "pathway" style games where routes - road, pipes, wiring etc. - move from one block to another. Sprites can be guided from one cube to another to follow the routes. They can also be used as tokens in other games and if you like "tile" based games such as dominoes and mahjong you will see that there are even more possibilities.
To get an idea of what the cubes can be used for take a look at the video:
The claim is that playing with cubes improves spatial reasoning, strategy and planning, patterns and perception and cooperation.
The cubes don't have much computational power and the logic is controlled by a PC (only Windows or Mac at the moment) via a USB wireless dongle. The PC has to be on and in communication while the blocks are being played with. Each cube as a 32-bit ARM processor, 8Mbytes of flash memory, a 128x128 LCD display, a 3 axis accelerometer and a custom near field sensor.
An SDK will be available in September and you can code in C# using Mono. The SDK will allow programs access to the sensors in each cube including the neighbour sensors and the accelerometer. You can sign up for more information on the site. There is also a Creativity Kit that allows end users to customize games.
To play with the cubes you need to by a starter kit which has three cubes, the PC interface and software for $149. Additional cubes (up to a total of six) are $45 each and the hardware should be ready to ship in September.