I did exactly this in July. My colleagues and friends were surprised that I didn't have something else lined up, but I needed to take a full break from the 9-5 world. Funnily enough I had about 6 months of runway too.

Several comments in this thread have mentioned how it's hard to get a side project to profitability in 6 months, but that's really not the only route to a sustainable lifestyle. Freelancing, consulting and other income streams (hurrah for busking!) are all perfectly good ways to try out new projects, learn or improve skills, and bring in some cold hard cash.

I've personally found that far more doors are opening for me now I'm open-minded, available, and willing to have conversations. When I was equated with the tech company I worked for, people would not have approached me about the things they do now, and I certainly wouldn't have considered some of the things I'm considering! It's taken a few months but I'm happy with where things are going, excited about the various projects I'm doing, perfectly satisfied not to have a complete prototype of a fundable startup idea yet, and definitely still overwhelmed at the sheer amount of branching futures ahead of me.

Good luck!