We have just started with this Vocabulary Building curriculum and I rather like it. I download the audio presentation from the Wordly Wise website and add it to our iTunes "Daily Listen" playlist, which I will tell you about in an other post. After a couple of days of listening, we tackle the worksheets. The children get most of the answers right and feel all clever and "Good at English". The webiste also includes fun review games which are a nice carrot for children who complete their lessons promptly.
Besides, what's not to love about a curriculum that includes this sentence: "Only the Congress of the United States has the authority to declare war."
P.S. Just found the Wordly Wise Word Lists here, so if you wanted to you could just work with the word lists and the audio and the games.