AVGA is TILE-based AVR interrupt driven audio-video driver for a single-chip game console. Or: It's a great board for developing and prototzping AVR video stuff!

Arduino Nano is a surface mount breadboard embedded version with integrated USB. It is a smallest, complete, and breadboard friendly. The Nano was designed and is being produced by Gravitech.

DS brut is an open source hardware prototyping platform for the Nintendo DS

This device, based on an Atmel ATMega168 microcontroller can monitor up to 16 DS18x20 thermometers, with a variable logging rate of 5 to 9999 seconds. The data is displayed on a multi-page LCD display for immediate viewing as well as being sent via RS232 at 19200 baud for recording. Data is time-stamped with an optional on-board 1-Wire real time clock.

A quick prototyping system that will plug into a breadboard without taking up too much space

Metaboard is a USB based prototyping board for Atmel's AVR microcontrollers. It is designed to be (mostly) compatible with Arduino. Its entire design (hardware and firmware) is Open Source.

A GPS data logger that records position data from the GPS module. The position data is received in NMEA-0183 format and store its sequence into any storage device. The position data can be processed with existing GPS utilities for interesting applications.

The MMC-FAT Bootloader project bridges the "bootstrap gap" for an arbitrary set of target hardware that follows a streaming serial bootloading protocol. It connects to an MMC disk through the ATmega168’s SPI by using the MMC bus protocol’s SPI mode. It connects to the target device through the ATmega168’s USART interface.