One of the most exciting things about the internet is the wonderful opportunity to learn new skills and expand our knowledge of all sorts of subjects. Many of these opportunities are entirely free, and through doing courses that appeal to you, you will meet like-minded people all over the world.
I will start by suggesting some sites where you can learn more about the internet, how it works, and how to find your way around and get the best out of it.
Internet for Beginners - a good site specially for beginners
Worldlinklearning  - basic information for older newcomers!
Livineasy  - another site designed for older beginners.
Steve Grossman's site  beginner tips - use the menu at the left
Northernwebs - lots more information for beginners
A Very Special Site
Sparknotes - unlike other study guides written by disgruntled academics and stodgy old professors, SparkNotes are written exclusively by students and recent graduates. Over 100 Harvard students and graduates have contributed to SparkNotes. All of the writers specialise in the subjects they cover--you'll find History PhDs writing on The Fall of Rome and Astrophysics grads covering the Planets. SparkNotes has expanded its literature collection and now also features over a dozen channels with guides on everything from ancient Greek philosophy to special relativity.
Reference Sites
You will find many more useful sites listed in the Information section.
Grammar. spelling and punctuation- a very helpful reference site
One Look - several dictionaries, one search
Encyclopaedia Britannica - THE encyclopaedia... with some modern additions!
Online Courses
Freeskills free online training - real free education
The Virtual University - free life long learning courses in writing and the arts, history, philosophy, webdesign, hobbies, almost everything you can think of.
There are also tutorials on a huge variety of subjects - you can use the tutorial search engine I mentioned in the Search Engine section. 
Some of the subjects you can learn more about are how to play the guitar, paint using watercolours - there are many sites for this, including  Wetcanvas; you can learn how to teach children to sail a boat safely at Kids in Boats, as well as myriads of computer-related subjects (you will find over two hundred of these at Edsurf:- The Online Distance Education Learning Resource for Adult Students.