I use a loose form of cooperative learning every day. Students always have the option of working together or in groups. Unless there is a major cheating or behavior problem, they can work with whoever they want to whenever they want to. I find that students are more engaged because each group is talking rather than just listening to me, or listening to one of them talk at a time.
They also the like the choice and freedom that comes with choosing a group to work with. With very few exceptions the kids who attend regularly and understand assignments are more than happy to help those that have missed class or are having difficulty. I can't think of a student who would rather move ahead at the expense of his peers. Most students are willing to help each other along so that they can all move on together.
I teach special education, so I have smaller classes, and the instruction can be individualized fairly easily. Students all do the same activities, but at their own pace, and their grades are based on how far in the curriculum they go each card marking. That also makes the cooperative learning a natural fit: everybody is always doing his/her own thing and they can join with others who are doing the same thing.
Ultimately, letting students work cooperatively mimics the real world, increases time engaged with the task, increases participation, and makes students happier. Sure, it is no perfect world in my class. Working cooperatively also means kids have more opportunity to gossip, copy, mooch, or hold themselves back while they "wait" for a work group member. But, compared to my old days as a lecturer where students just zoned out all hour, this is a HUGE improvement in the use of time. Even with the occasional off task behavior (my role is more facilitator and task master), they are still more engaged (not passive lecture recipients), and I hear some really great conversations and teaching going on between peers.
One of my best activites was about solving algebraic word problems in grade 9 -- the ones where students must generate the equation themselves. I set up 5 groups and assigned 1 type of problem to each (coin, distance, age, etc.). We had gone over problem solving briefly so they knew the steps (Let statements; work chart; equation; solution steps; solution statement) I wanted them to use. Each group's first task was to solve enough problems to make all of them experts in their type. I assessed this with a quiz -- they all had to get 80% or better. Then they had to make an easy-to-follow poster to show others how to do this, present their steps to the class, and finally become the 'goto' experts for that type of problem when anyone had difficulty with the mixed problems assignment. I put up the posters up in the hall for others to see what was going on in my math class. I even caught a number of students from other classes using them!
If you are new to cooperative learning you can start with 2 simple activities:
One is called pair check, later it can grow into pair share.
When students come to class you give them a number. The first one is #1 then the next person is #2 and so on. You have your regular lesson, but in the middle you remind them of their numbers and give each pair a piece of paper folded in half. One half for #1 and the other half for #2. They have to pass the paper to each other on your command. Practice with them, let them laugh and have fun. After a while they will be eager to participate. It's a game.
In advance you have to prepare 4 questions for each #.
First the paper goes to #1 s/he has to answer to the first question. Make it 30 second question one-word answer to keep it fast. (if it goes a little slow don't worry)
Paper is passed to #2 You give them the answer to question 1 and make them to give a check to #1
then you give them their own question 1 to answer on their half of the paper. (again no more than 30 seconds, easy question)
Paper is passed to #1 to check the answer of #2 and record their answers to question 2. You continue all 4 questions to each #. You make them give each other grades, and you record those grades in your real record book (don't worry if everybody got a 100 :) Hang the papers on the bulletin board. Enjoy this activity once a month or more often. It works with every age group. My HS students love it.
The other is called Carousel or Mary-go-Round there are 2 ways to play it.
One: you hang a large poster paper in every corner of your room (if you have 4 groups, for more groups more posters)
Each poster has 4 questions (or 6 or 8 it depends on the number of the groups) with spaces to write the answers.
Each group has a number same question number on each poster they have to answer. Group 1 answers question #1, group 2 answers question #2 and so on.
If you have 4 groups each group has 10 minutes to answer the question on each poster. In 10 minutes they move to the next poster. If you have 8 groups the time is 5 minutes and so on.
Now how you organize your questions: Each poster has to represent different area of knowledge.
In my case The questions were divided by BIOMEs.
Poster 1 was about desert,
2 - rain forest,
3 - taiga,
4 - tundra.
Question 1 on all posters was about the temperature in the Biome, so group 1 was temperature specialists.
question 2 about rainfall, group 2 - rain specialists
question 3 flora, group 3 plants specialists
4 - fauna, group 4 animals specialists.
You have to create all these questions for your classes in advance, but when this is done you just sit and command when they have to move to the next poster and remind them to read everything each group wrote. At the end group #1 stands back at the the poster #1 and reads all the answers. Can be used as review at the end of each unit.
In the other method the students are sitting at their desks and the poster is moving around the room, depends on the dynamic of your classes and whether you allow them to use the textbooks.
There are more cooperative learning activities, but you have to feel the success and fun before trying them. I learned a lot about my students when I started to use these methods.
Sorry, it came out too long :)