Reading. I absolutely love it! You can learn and develop the mind so much by reading. I cannot get enough of a good book caressed by a lovely, warm, sunshine-filled day!
I believe all unsolved problems stem from a lack of knowledge; for how can you solve a problem without a solution?
The beauty in the era we live in is that knowledge really is at the edge of most of our finger tips. We need only flip open the page to get ahead of the game!