>   Which programmable robot you'd recommend to inspire and excited K-12
>   kids about AI?

In my view, robots that lack computer vision cannot be used to teach
kids much about AI.  This rules out most of what's currently available
in the K-12 marketplace, including Dash and Dot, Sphero, LEGO, and Vex.
Note that a simple brightness detector does not qualify as "computer
vision": see the distinction between "sensing" and "perception" in the
Five Big Ideas.  Real computer vision means things like face detection
and object recognition.

So what robots qualify for teaching AI?  Here are three you can get today,
and three more that are coming.

Today:

1. Cozmo -- by far the best price/performance of anything on the market.
Suitable for ages 8 and up; can be programmed in Scratch, Python, or
Calypso.  And still available for purchase, even though Anki has gone
out of business.  Get them while you can; there won't be any more.
  https://anki.com/en-us/cozmo.html
  https://Calypso.software

2. Robomaster S1 from DJI.  Just released.  Robot tank with a built-in
camera on a pan/tilt mount.  Programmable in Python.
  https://www.dji.com/robomaster-s1

3. Autoauto.  Robot car with built-in vision, but very limited control
primitives.  Students are expected to figure out their own control laws.
Programmable in Python.
  https://www.autoauto.ai/

Coming soon:

4. Amazon DeepRacer: a vision-guided robotic race car.  Was promised
for July but now expected to ship sometime this fall.
  https://aws.amazon.com/deepracer/

5. Sphero RVR: a robot tank that you can bolt a vision module onto.  Supposedly
has really good odometry.  Due to ship in October.
  https://www.sphero.com/rvr

6. Zumi by RoboLink.  A tiny robot car with a Raspberry Pi 0 offering
some computer vision.  Crude control due to lack of odometry.  Was
launched as a Kickstarter; not shipping to new buyers yet.
  https://www.kickstarter.com/projects/robolink/driving-into-the-world-of-ai-zumi

-- Dave