it = activity But I think "Activity" here refers to "Activity Card" as you have spelled it with a capital letter.

Hello Mr. Dima: I think that that there are cards which serve like "Wild Cards" in Poker. It is similar to the idea of one suit of the four in a deck of cards, being designated a TRUMP suit. It counters, or captures, any card of the other three suits. In this game it appears that you lay the cards with the power to "cancel" the effect of an Action Card, in front of you. Thus, as the Action Cards are played, you have the option of using your "Cancel" card on a one time basis. . . You wrote: "When player plays Activity cards, he puts it in front of him to the rest of the game. These cards are called "Played cards"." [This would usually be written this way I think, as follows]: . . "When a player plays [ or uses] Activity cards, [on his turn] he puts it in front of him FOR the rest of the game. These cards are called "Played cards". [The will probably be laid face down or face up as the "Played Card" which you do not touch again] If it is your turn to play, you probably have the option of using your own Action Card, or you can play the Cancel Card that you might have, and Cancel whatever action, the previous player's card indicated. Thus, you manipulate them, rather than being manipulated by them on your turn. This is just an educated guess. I have never seen the game.-Warm Regards, Bruce