You might know this activity under different names. I worked with a teacher who called it the "alien game," and I'm sure there are other variations. You can certainly change the rules or name as you see fit!
The intent of the game is to get the students to practice a new grammar pattern. It works best with grammar patterns where sentences can be divided in half and combined in ways that still make sense. Something like "I can... / ...play baseball." "She can... / ...speak English."
There are two ways I've played this game, but for both, you'll need to pass out the papers first. I draw a treasure chest on the board and tell the students to draw five of them on their worksheet in the chart. It can be an elaborate treasure box or just a simple square or circle, as long as they have five of them. I tell them to keep it a secret from their neighbors, as this is part of why the game is fun.
Playing as a class
I draw the chart up on the blackboard and write the sentences out. I ask the students to repeat the sentences in the chart, starting at the top left and going diagonally down to the bottom right. This helps the students have a little more confident speaking the sentences, especially if they contain some new vocabulary. Next, I choose one square, point to it, and read its corresponding sentence ("She can / play baseball.") I then draw a big X through the square - I've attacked that square! All of the students have to draw an X through it, and if they had a treasure in that square, they've lost that treasure and now they're down to 4 treasures. In my experience, explaining that everyone needs to draw an X through the square is the toughest part of this game to explain, but once the students understand it, the rest of the game should go easily.
I usually ask the JTE to make another sentence based on one square in the chart, and once they've said it, I cross that one out too and make sure the students cross it out.
At this point, I ask all of the students to stand up. If they raise their hand and say a sentence, they can sit down. Generally, the strongest students will understand this first and provide an example for the other students in the class. As time goes on, more squares will get crossed out and students will lose more and more treasure. By the time you get down to the last two or three squares, you can make more of a dramatic show of it and ask students how many treasures they have remaining. The winner of the game is any student who has a treasure in the last remaining square that isn't crossed out. There really isn't any skill involved in the game (aside from knowing that the bottom right area tends to get chosen last) but the end of the game gets tense and fun for everyone.
Playing in pairs
The game still has the same rules, but you can have the students play in pairs instead of as a full class. You could even do it as a "Round 2" after playing with the class. It gives the students much more individual speaking and listening practice, but if you're worried that one half of a pair might not participate, you could have the students play it in groups of 3 or 4.
My example pages use a 5 by 5 grid, which gives 25 squares, but depending on your class size, that might not give every student a chance to speak. You can add in another column or row (it's just a standard Word table) or build your own chart if you need more squares.
I've attached several variations I've used for different grammar points, but of course, you can alter these to fit what you want to practice!