Two web sites that have been effective in my classroom are jeopardylabs.com and the sadlier-oxford.com
I have students work in groups to create a jeopardy template for review of Antigone. It was easy to check because they had to provide the correct answers.
As for the vocabulary workshop, it has greatly improved scores for the students who utilize it. It is easy to evaluate because the site gives the students a score when they finish a section.
I feel it is important to tie technology to learning objectives because it adds excitement to the lessons. My students don't feel like they are working when they visit these sites. They feel like they are playing. They have created their own jeopardy templates for review.