I only put links on the Favorite Sites section on my English Themes For Beginners page that I think are very superior English language development activities. I’ve just placed a new site in that section.
Wordbuilder is an excellent spelling, vocabulary, and phonics site from Houghton Mifflin. Students are told a word, in the context of a sentence, and then have to spell it. It’s designed as a game, and there are literally hundreds, if not thousands, of opportunities to play. It’s appropriate for beginners through Intermediate English Language Learners. Audio and text support is provided.