I got laid off from my job at the beginning of summer. Over the summer I helped a startup (which I thought I was going to be partners with but they decided otherwise), made some small demos exploring some interaction ideas, and spent time interviewing for other positions / traveling for a couple weeks.
Some of the interaction ideas were intended for another mini startup idea, but after demoing prototypes I wasn't happy enough with the response - it was a "oh that's neat" but not enough "please take my money". I'm now trying reapplying the ideas to a use case with a more interesting business plan.
On the plus side, I now have an on-going part-time contract job where I work from home. Surprisingly I almost make the same if not more money now with less hours, go swimming during lunch, and have time to focus on side projects.
I'm seriously thinking about moving closer to the mountains.
Do I recommend getting laid off/quitting? No. I was honestly freaking out for the first 2-3 months of summer. I was a bit lucky that I already had some companies calling me a week after I was laid off.
Do I recommend always putting in a couple hours every day on a side project? Yes. Get some idea of whether your idea will work out or not, and do your customer problem/solution interviews. Go to coffee shops/libraries to help concentrate.