Depending on the native language(s) of the students you teach, you might want to send your students to Duolingo for independent language learning and practice activities. Duolingo is a free website and app designed for language learners. It is absolutely fantastic!
Register to get started. Once registered, you choose your native language to see what languages are available for you to study. If your students speak Spanish, Portuguese, French, Italian, German, Russian, Hungarian, Turkish, Mandarin, Dutch, Polish, Japanese, Romanian, Hindi, Indonesian, or Greek as their native language, then they can start learning and practicing English on Duolingo today. It looks like speakers of Arabic (the one I am most interested in currently) and Korean will be in luck soon, too. Unfortunately, there does not appear to be a course designed for students to learn English on an all-English platform at this time, so if your students speak other languages as their native language, they will have to wait for a course to be developed.
After you choose your course, you can enroll in a basic course or take a placement test. I tried it out with Spanish and was pleased with the overall look, feel, and quality of the site. Everything is interactive and feedback is immediate. Students can often read and hear the material they are working with and there are quality images to help make connections with new vocabulary. At the basic level, students are prompted to connect words or phrases with translations or pictures and even record themselves speaking the target language, so reading, writing, listening, and speaking are all developed at the same time.
Progress is tracked and points are earned in a way that makes language learning seem almost like a game and encourages continued participation. You can see what is coming up in terms of topics, but you cannot skip ahead. There is even a social aspect where you can compete with your friends or discuss your learning with other users. Additionally, Duolingo has its own currency, called a Lingot. Lingots are earned through activities on the site and allow you to make purchases such as power-ups and even access special course materials. There is just so much going on on this site.
I have only just tried Duolingo out a little bit so far, but I will definitely be going back to work on my Spanish and would recommend it to students if English courses have been developed for their native language. You can start learning a new language to test the site yourself, but I am sure you and your students will enjoy it.