One of my very first attempts was to build a tutorials site where I'd write stuff on photoshop, php, css, html, etc. Wrote a few tutorials, (re)designed website over 10 times before launch, but did not get any traction. Gave away my tutorials to other sites in the ecosystem. (
https://web.archive.org/web/20050208112644/http://invano.com...)
About the same time someone told me may be I should build sites where people can contribute and I wouldn't have to worry about creating content. So, I created this search engine that would index tutorials from all other sites. Built the back-end and some front-end but gradually lost interest to another project.
Then I built this another site with tools for webmasters. This was actually launched with some modest success as by this time I had learned enough about Apache/PHP/MySQL etc. (https://web.archive.org/web/20051215081101/http://viewhtml.n...). But never figured out SEO/traction.
These were in high school and after these tries I gradually lost interest to other stuff. So that was that.
Then in college freshman year started this company to build computer hardware with my roommate. This was actually the first attempt to start a company. Everything else were just side projects. The idea was to build Dell equivalent for Linux.
I think I read this note on some mailing listing about why Linux was not widespread (Android was not mainstream, yet) because there was not any well established distribution mechanism. There was a need to build an equivalent of Dell that would ship computers with Ubuntu and provide user support.
So we bought off-the-shelf parts to build our first desktop computer to sell, built it, and installed Ubuntu. Then my roommate and I had a fallout. So that was the end of this.
And there are a couple of more things that didn't take off. But life was not really impacted drastically as all were learning experiences.