Here are the most useful links for learning spanish on the internet that will make you smarter, increase productivity and help the students learn new skills.
Practice Spanish grammar on line:
http://www.indiana.edu/~call/ejercicios.html
Short videos in Spanish language
On-lineSpanish TV
Read short stories in Spanish
http://cvc.cervantes.es/aula/lecturas/
Games in Spanish
http://cvc.cervantes.es/aula/pasatiempos/
Children story books in Spanish
http://www.mundolatino.org/rinconcito/arcoiris.htm
Jokes in Spanish
http://www.juegosdepalabras.com/chistes.htm