For robot LEDs you have a few options.
The easiest would be to use simple RGB LED strips like GeeTwo mentioned. For our bot last year we used these:
http://www.amazon.com/SUPERNIGHT-Wat...dp/B00B2F3KDQ/
The cool part is that they came with a controller that can be modified to work with the RIO outputs. If you open up the little white box, you can find the three FETs that provide power to the strip. Just desolder control bits, and solder in some PWM line. These can be fed directly from the RIO by a real PWM (not a servo or motor controller PWM) to get RGB control. The 12V jack wires up to the PDP, and you're good to go. You can also use a Spike if you don't want to putz with soldering in PWM lines, but you can't generate fluid animations or different brightness levels.
The next step up is to use addressable LEDs, but it adds some significant complexity. This year we used these:
http://www.amazon.com/NEWSTYLE-Progr...dp/B00MHUK83K/
Adafruit sells them as NeoPixels, but they are all based on the WS2811 or WS2812B LEDs. To control these, you need a dedicated micro-controller on your bot since the RoboRio doesn't have the real time digital support to do it. You also need 5V for these, not 12V. A quick note on that, the 5V on the VRM poses a few problems since it's noisy and you really want to leave that 2A port for the radio. If you still have it, the vreg from previous years works well, or just search amazon for a UBEC (a regulator for RC cars).
The simplest method to make these work would be to have some programmed animations on a micro-coontroller, and then use a few DIO from the RIO to your chosen micro to select the animation. One more step up would be full digital communication. We used the I2C port on the RIO to communicate with a TI LaunchPad (like the one in your kit). The LaunchPad then made decisions on what to show on the strip. Since this gave us some flexibility, we ended up with two separate strips that can have their own animations from one LaunchPad.
Feel free to let us know what direction you're leaning, and I'm sure the forum can get you some more technical info.