Startup or fun project?

I'm a MIT grad with an MBA, and 3 bachelors working in finance. I work alone and from home, and make enough to keep the 9-5 away, but recently it has gotten boring. I normally only work 3 hours a day and have nothing else to do afterwards. I used to work a 9-5 for most of my life, and miss the feeling of having something to do and eventually left because I got tired of working in toxic work environments and insecure micromanagers. I thankfully have the opportunity to work on my own now, but I would love to start a startup or a fun project with people who feel the same or are in the same scenerio.