Hackaday: modifying technology, or "Hacking" is a great educational and fun pasttime. This blog is great for ideas on modding your life and working with classes on computers and other electronic devices to make useful things from discarded stuff and learn about electronics, etc.
Make Use Of: tutorials, websites, hacks, and resources that you need to make technology work well for you - sign up for their newsletter to get a digest of their weekly scans of useful. Very much a "lifehacker" site.