LED Matrix 8 x 8 Red with SPI Interface MAX7219. 

Easy to interface to any microcontroller with SPI including Arduino.

Various libraries available. LedControl is perhaps the easiest to use. 

Specifications

8 x 8 matrix
Hi Red color
3mm LEDs
Common cathode pins - easy to drive with included MAX7219
Face color black
Lens epoxy color white, diffused
5 f-f ribbon cable