1. Statistics – People site statistics all the time to back up their claims. You should be able to understand what the numbers really mean. Khanacademy.org has a fantastic course on the subject.
2. Nutrition and Fitness – You only have one body, so you better learn how to take care of it. Check out simplesciencefitness.com for a comprehensive look at the subject.
3. Sex Ed – You will probably have the desire to enter intimate relations with another individual. You should learn how to do so safely and responsibly. Dr. Doe has a great YouTube channel on the subject.
4. Cooking – You eat three meals every day. Learning to cook will save you money while still allowing you to eat delicious food. Check out this post for useful cooking websites.
5. Computers – They are a part of everyday life. You better know how to use them. You can learn about the basics at thinktutorial.com. For more on how a computer works, check out Professor Messer over at YouTube.
6. Personal Finance – Money very much dictates how you live your life. You better learn how to make the most of it. Check out I Will Teach You To Be Rich for the basics of personal finance.
7. Game theory – Learn to assess risk versus reward in any situation. Check out this Yale course on the subject.
8. Philosophy – Philosophy teaches you how to think and question things. Check out this Yale course on the subject.
9. Politics – Your government heavily influences your life. You should learn how it works and how you can contribute. Crash Course over at YouTube has a great rundown on United States government and politics.