There is no question that you can build all kinds of interesting things with LEGO Mindstorms sets. Take this LEGO Halloween Candy Thrower for instance. It is a fun little robot that throws chocolate bars and candy. It has an infrared sensor to detect when someone is in front of it to deliver.
As JK Brickworks explains, all the parts for this robot are in the LEGO Mindstorms EV3 31313 set. The robot doesn’t have advanced computer vision or other fancy features but seems like an interesting project for those of you who have young kids around.