Two kinds of game thinking about information

Game systems basically have 2 different ways of looking at information: either some or all of it is hidden or it's all there in front of you.  Many games have elements of both.
For example, in chess, all of the pieces are there in front of both players.  I may not know what the other player is going to do, but there's nothing to stop me from guessing and anticipating because in theory I know as much as my opponent does.   Compare this with poker in which there are three ways in which information is hidden and revealed: 
1. the face-down deck on the table hides cards that no plyer has
2. the other players have cards that I can't see
3. the other players try to misdirect me and feed me false information by bluffing through the way they bet

In the classroom, traditionally information is fed in by the teacher and vomited back out by the student.  A disgusting analogy to be sure, but quite true if we realise that very little of the information stays with the students after the test.  However, we can play with information in the classroom too.  For example, instead of telling the students how something works or having them read a text about it from beginning to end, we offer them a cut-up text to put in order.  This is an example of a situation where all of the information is there, but manipulating it in this way will aid retention.  Or as an example of a task with hidden information, we can cut up the text and give different pieces to different students.  Each student can only answer questions once they've gotten the information from the others.

Another way of getting information is by exploring.  Many video gamers spend a lot of time simply wandering around the game space getting to know the layout.  In fact, there is a game called Doors and Rooms where the player simply explores the space trying to figure out how to get out.  Unfortunately, true exploration requires time, which teachers just don't have much of making it difficult to tell students "go and find out about X".  A shortcut, then, is a webquest in which the teacher has preselected from 6-12 sites which the students have to visit in order to find specific information.

What are some other ways you hide or reveal information to your students?