Control window blinds, lights, and monitor battery charging using voice command.
A Maker interface to the Alexa Smart Home, using Raspberry Pi, Gobot and Arduino's Firmata Protocol at home, and AWS/Serverless on Cloud.
Amazon released an AWS IoT button but made it really difficult to get a hold of. Why not build your own and customize it to your liking.
Use Amazon Web Services to coordinate control of many (swarms) of $20 radio receivers, creating a giant virtual radio scanner and monitor.
Smart Dustbin - it monitors waste in real-time and alerts when full with an LED, keeping our world cleaner and free of overflowing trash.