You can learn English also for fun. You may find the following links interesting for your personal interest in the English language. Here are links to idioms, slang, fun facts, famous quotations… Hope you'll enjoy them!!!
IDIOMS
DogHouse Idioms
The Dog House - Idioms
SLANG
http://www.daveseslcafe.com/slang/a.html
Dave ESL Cafe's Slang Page - Slang