said by inGearX:can u suggest any other cool tips / tricks ?
A very cool, and probably not so known, feature of Wikipedia is the ability to create a book from several articles. You can find it in the left navigation bar under Print/Export -> Create a book.
You can choose if you want it as PDF, epub, etc.
For my holidays last autumn I created an epub with a lot of articles about my destination. Saved it, uploaded it to my iPad and took my custom made travel and history book with articles, pictures, maps, etc. with me. Much better than a commercial travel guide.