FEZ Mini is a tiny board running Microsoft .NET Micro Framework. This means, you can write code with much more efficiency using C# programming language under free Microsoft Visual C# express. The pinout is BasicStamp2 compatible.
Many libraries are already included like FAT file system on SD cards, threading, UART, SPI, I2C, GPIO, PWM, ADC, DAC and many more.
Note: Unlike FEZ Domino, FEZ Mini doesn't have USB host; therefore, it can't be connected to a USB Memory stick or other USB device. But, it has USB client port to connect to a PC.