I also ordered one of these

amongst other things. Should be fun putting these together.
Any ideas of what I could build? I was thinking of building a robot that avoided obstacles at first, but that's a bit too easy and should be done in only a few hours. So I need something a bit more challenging.
I have made a list of things I want it to do. If you have a cool idea to add to the list, please do share it

Avoid obstacles using infra red sensors on all sides.
Motion tracking with a cheapo web camera mounted on a tilt/pan bracket with servos.
Voice commands, such as Forward, Reverse, Stop, Turn left, Turn right etc.
Some sort of text-to-speech. Because there is nothing cooler than having a conversation with a robot. Even if the robot is infinitely stupid.
Auto navigation(Set a destination and it knows how to get there by itself).
That's what I've got for now. It's not a lot, which is why I'm asking for inspiration

If anyone is interested, I could post the progress here once I start building!