Youtube is a good one I think. They have lessons and endless amounts of practice.

But these websites should reflect the personality of your students. Is one majoring in zoology? Then recommend a website based on that. (But I don't teach English so I may be stating the obvious or something way off.)

Not much time, but

http://www.scribd.com/doc/3099185/The-Oxford-3000-words (tell them to buy the book, as this PDF is pretty naff.)

Googlebooks (previews of kids books - same way we do it)

Various nameless manga distribution sites (the ones people use to read stuff in English, of course.) They all know certain manga quite well, so it's easy, yah.

Google (search terms: ESL lesson, etc.)

http://www.scribd.com/doc/6001254/3000- … in-English (just a pdf from one of there courses, but pretty useful.)

http://rfptemplates.technologyevaluatio … -list.html (ignore the advertising)

Idiomsite.com

http://www.keepandshare.com/doc/12894/adjective-list (good list of adjectives)

http://www.paulnoll.com/Books/Clear-Eng … verbs.html (adverbs list)

http://www.englishclub.com/vocabulary/r … s-list.htm (verbs list)

http://www.momswhothink.com/reading/list-of-verbs.html (this is an absolutely awesome site for words)

about.com is good for grammar.

the owl purdue english lab is very useful if they are at a higher level.

Sorry, I would add more, but times up.

Soooo cute! 204 videos in the play-list
Ayaka's Surprise English Lesson