Robotis has released plenty of awesome robots for kids and adults in the past. The Robotis Engineer Kit is a STEM kit that comes with everything you need to build cool robots. You get a ARM Cortex M4 MCU, servos, and all the parts necessary to put these robots together.
You can 3D print end effectors to customize the robot and program it with R+Task software. The Robotis Engineer Kit has SPI, MAX-E1 and Dr. R modes. It can be programmed with a PC or mobile device.[where to find it]