I made https://jsmess.com as one of my first vibe code projects and have been incrementally improving it over time when I have leftover tokens...

It's closest to JSFiddle but completely static, hosted on GitHub pages. No server side processing. Projects are private, saved on localstorage and can be shared via encoded URLs.

This has been a really fun way to ramp up with LLM based coding and I learned a ton, and made a tool I actually use quite often.