One of the MOST important skills students need to be successful in college is the ability to synthesize multiple sources to support an argument.
This lesson takes a relevant topic: social networking and walks students through the process of using two sources to support their own argument.
It is highly scaffolded and includes extensive teaching suggestions. The culminating product is, of course, the synthesis essay.
I've used this multi-day lesson with sophomores and juniors- both on level and AP. It works like a charm:)