Use an empty bag and put something inside (anything will work!)
Make a chart on the board with a "yes" column and a "no" column.
Students ask yes or no questions to determine what is in the bag.
(You may want to limit the number of questions so that they will think before they ask questions.)

If the students asks, "Is it a toy?" - write the word "toy" in the appropriate column.
After a certain period of time review the yes answers and the no answers.
Allow the children to guess what is in the bag.
Once you have a few guesses, you can let the children vote. Ex. How many of you think it is a rubber band?
Record the votes, and finally....let the child who has been extra nice pull the item out of the bag.