The Make Controller Kit is a high-performance 32-bit sensor interface featuring Ethernet, USB, ADC, high-current outputs, JTAG, many kinds of motor control (DC, servo, stepper), CAN, RS232, and more by MakingThings. It is an open source project - all the firmware, software tools and schematics are freely available.
The board by default runs a program that allows it to connect to other devices via OSC over Ethernet and USB. It's also easily reprogrammed via USB to run user-written programs standalone/embedded. It's easy to connect to any of the normal desktop environments that support OSC - Max/MSP, Processing, Flash, SuperCollider, etc.
The board currently runs OSC over both USB and UDP - we're hoping to get it up over TCP, and Zigbee as well, among others.