SparkFun's minimal design approach to Arduino. This is a 5V Arduino running the 16MHz bootloader (select 'Arduino Duemilanove w/ 328' within the Arduino software).
This is a 3.3V Arduino running the 8MHz bootloader, in a very small package - a Mini Arduino, you might say!
You need to wedge an Arduino into a really tiny spot? Simple - just use a SMD '328 IC. Oh... you want a reset, and voltage regulator too? Why didn't you say so!
This is a Arduino-compatible autopilot board designed by Chris Anderson and Jordi Muņoz of DIY Drones using the new ATMega328. This board was used to win the annual autonomous vehicle competition put on by SparkFun
Looking for the smallest Atmel microcontroller with built-on motor drivers? The BittyBot MEGABitty microcontroller features an Atmel ATMega8L, motor drivers, and voltage regulation in tidy 0.9" x 0.9" package!
Simple target boards for ATtiny2313 microcontrollers and mini-development kits.
The Netduino 2 is an 32-bit open source electronics platform using the .NET Micro Framework with a rich development environment.
Netduino Plus 2 expands on the impressive 32-bit open source Netduino by adding ethernet connectivity and an SD card socket.
The Netduino mini is a breadboard-friendly of the impressive Netduino development platform that uses .NET micro framework.