Effect : While you are out of the room, or have your back turned, people select any item in the room to think of. When you return, a friend points to a bunch of items slowly without saying a word. You announce what the item is - and you are absolutely correct!
Secret : Your friend is in on the trick and acts as your assistant. The third object he points to is the chosen item. Wait until a few more objects are pointed to before making your revelation. If you are asked to repeat the effect, use the fourth item the next time!