Which websites have you found most helpful up to now. I’m talking about edifying, clean and useful websites (or that were intended to be used for the good of us all) that you could recommend to your favorite teacher or even to your mother. There are some I find extremely useful like www.wikipedia.org. Please share some of yours. It could save other viewers years of searching for the right website.
“Convert anything to just about anything else.” It’s pretty much true at: http://www.onlineconversion.com/
Except it doesn’t convert Lunar year dates to Gregorian and vice versa. So, to find out when my parents’ birthdays fall this year, I still have to consult a paper Lunar calendar given as a gift by a bank.
M-W Dictionary, has audio pronunciation files
Skeptic’s Dictionary, all my childhood superstitions destroyed
Better than that, http://www.onelook.com. It searches all the dictionaries on the Internet. It’s my best-kept secret, so don’t tell anyone. 
snopes.com is great for researching information about urban myths.
npr.org is a nice site and is a little like a coffee table magazine my parents would read.