Many of the interesting webpages that I found were from this website:

INTERESTING THINGS FOR ESL STUDENTS
http://www.manythings.org

Some of the good links from this page are listed below:
(You can get to these links from the Site Menu of the main website)

Commonly-Used American Slang
http://www.aitech.ac.jp/~itesls/slang

Daily Page
http://www.manythings.org/daily

Proverbs
http://www.manythings.org/c/r.cgi/proverbs

I also recommend these choices from the site menu:

-Concentration
-Hangman

Another great Hangman game is found on:
Readers Digest
http://www.readersdisgest.com
You can find articles and other features, such as Hangman ( a game for practicing spelling and vocabulary)

Idioms
The English Learner's Movie Guide
http://www.eslnotes.com/home.html
This website provides synopses of forty two movies.  Extensive vocabulary explanations (including a lot of idioms) are provided.
 

Look at some of the websites on this list, or from the handout the Best of the Web and try writing your own
website reviews.