Spanish Proficiency Exercises is a compilation of video clips in which native speakers of Spanish from various locations throughout Latin America and Spain demonstrate various language tasks.

This fun, problem-solving app can be played in several different languages. Users must provide the word that four given photos have in common.

This is widely-regarded as the best online Spanish-English dictionary. Searches yield detailed results, including forum discussions, relevant grammar links, and verb conjugators. (Other languages are included, but I can't personally speak to their usefulness.)

This is the Spanish teacher's go-to website for authentic language, music, and culture activities.