A matrix of 4×4 fully addressable RGB LEDs in the big 5050 SMD package (5×5 mm), compatible with Adafruit’s Arduino library for WS2812 LEDs (google for “neopixel” library).
The modules can be cascaded to build bigger clusters.
Every LED contains it’s own 18mA constant-current driver, and an addressable driver chip, and will work without any current limiting resistors on a power supply of 4-7V.
Since the data protocol is quite timing-specific, you will need a faster micro controller (at least 8MHz) to control it. You can use it for example with an AVR and Arduino, PIC, STM32 or similar controller. You will have no luck with “interpreted” controllers like Basic Stamp or Picaxe.