Beehive activities.
 

This activity is for large classes. Simply go to one of the rows either the far right or the far left. Ask a simple question for example. Hows the weather today? The students must answer the question and then ask the question to their neightbor. This activity continues in sequence until it reaches the other side of the room. This activity can get noisy. Its a good idea not to do for the whole lesson.

Is the question and answer a "secret"? i mean do they whisper them?

This is not Chinese whispers. Although Chinese whispers is a good way to introduce these kinds of activities. This is not a game. Its a drill. You should never try to do this for the full class.

So doing it for my entire 3 hour class is out? :p

Doing anything for three hours is a mistake. I've done three hour classes before and don't like them. Its usually to please administrative demands and has little to no educational merit. There are things you can do to make it less taxing on both you and your students. Sandwiching different kinds of activities together is a good idea. Since you're going to be spending so much time with them its a good idea to be stimulating their curiosity to keep the interest level high. Have you got any home movies of your family back home.

i was just joking about doing it for three hours. if i have classes that are 2 hours or longer I just treat each hour as a new lesson. The 2 or 3 lessons can be linked but the material needs to be new. At least this has been my experience. Covering one grammar point or topic for more than an hour and a half is too long.

As for length of activities, I try to keep them at 30 minutes or less.

A fifteen minute break between each 45 minute period is good