A few of my recent favorites: - swim lap counter in html/JS that uses the camera to watch you swim and count laps/timing - video recorder that records your window/desktop and uploads a file to S3 - video conferencing app that allows a 2 year to click on a family member face and initiates a video conference using webRTC, STUN, and browser audio/video capture with automatic bandwidth adjustments (works on all platforms with pure HTML/JS). - CUDA based ray tracer with HTML UI that can trace over 2m rays per second on my laptop for scientific study, allowing real-time display of optical parts. - chat front-end for image models like gemini-pro and openai that take other images and text as references and generate a big library of options to chose from in seconds, I've been using photoshop for decades but I tend to use this more now.