Enter this KARAOKE.

Getting ESL EFL students singing songs is a great way to improve their pronunciation, so here's a great karaoke site.

If you register, you can actually get a score for your singing when you hit the right notes. This could make the whole activity more motivating for learners as the site is giving them some feedback on their performance. If you got a whole class logged in they could learn their songs at home and compete for the highest score.