I recently bought a new toy. A Beagleboard from http://beagleboard.org/
It's a small board with a OMAP3530 processor, OpenGL ES 2.0 capable 2D/3D graphics accelerator, HD video capable TMS320C64+ DSP etc.

Different projects exist to e.g. port debian and ubuntu to this small device.
Relevant links:
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Embedded systems