This past year I have been using Veinte Mundos with one of my advanced students to improve his Spanish listening and writing skills. This online magazine is perfect for students to increase their skills and learn more about the cultures that speak Spanish.
Looking through the library of articles you can see that there are all sorts of topics to choose from. Here are some that I have used in the past that are good...
Dulce de Leche-The delicious caramel of Latin America
El Guarani en Paraguay-The native tongue of Paraguay
Silbo Gomero-A language of the Canary Islands that consists of whistles
Each article (either categorized as intermediate or advanced) can be listened to as your students read it on the screen. Within the article students can highlight a word and click it to see a definition. Besides the article there are tabs like the "lenguaje" tab that goes over grammar points, vocabulary, and has comprehension questions. Many articles have videos (under the "multimedia" and "viaja" tabs) to watch related to the article.
I created a worksheet to be used with any of the articles on the site. It is a place for students to record new vocabulary, color in a map of the country or countries in the article, and then write a summary of what they learned.