I can't agree with this enough. I'm kind of an old-timer web developer and have built about one new web concept every 3 or 4 years. While none of these ventures

I can't agree with this enough. I'm kind of an old-timer web developer and have built about one new web concept every 3 or 4 years. While none of these ventures have made me a millionaire, each one did teach me new skills and lead directly to my next job. Most recently it was a very fluffy "video sharing" rails app, built in 2007. It helped me get a good gig that buffered me through the first half of the great recession. Now I'm back to doing what I like doing best... investing time in learning and build-cool-thinging. I really can't lose. And, as a last note, building something is a very good cover for being, er, "in between jobs"... and a lot cheaper than grad school :)