- Duolingo – Learn another language
- Khan Academy – A fantastic way through youtube to learn about interesting subjects.
- MIT Open Courseware – free college courses online
- Investopedia – the subject says it all
- Quora – find experts to ask about almost anything
- Geography IQ – select any country and access virtually every facet of useful information
- TED – my favorite site on this list. Superb talks by interesting people from around the world.