At Horizon, we are big believers in both cooperative and integrated learning. Together, we call it Project Group. The students are usually posed with some sort of problem that they need to solve. They use information they learn in science and social studies, as well as writing and publishing skills developed in language arts. The key is that they learn to make decisions together and that they learn to not compartmentalize their learning. That is, what is relevant in science is relevant in language art, project group, and any other number of place.
Last year the students were working on building a "green" cargo ship. Below they are testing the efficiency of their sail designs. We built "Lake Horizon" in the courtyard outside my classroom.

They also tested to measure how straight their boat went and if moving the sails would impact the course of the boat.

This year we are working on the "8th Continent." They have learned all about how different landforms are made and how natural disaster effect all areas of the world. Their challenge, then, was to create an island based on a particular movement of the earth's plates; for example, a volcanic hotspot or a divergeent boundary. They are building these out of layers of styrofoam and it makes a horrible mess that will linger in the classroom for a couple of weeks.
Working in groups is not as common in language, but the students love it every time we do it.