You can do this as a group activity and you will need a whiteboard. (if you don't have whiteboards students can just say their answer) Choose 6- 8 students at random, and have all other students put their heads on the table so they can't see. Have the selected students write the same word in English on some scrap paper and swear them to secrecy. Give each student the same number as their handwriting so it is easier to identify at the end.
Ask all students to look up. Give each of the scrap papers a number as you hold it in the air for them to see. Ask the students to write the names of the students ( I usually have the selected students' names written on the board) and the number of the paper they think is theirs on their whiteboard.
Give the students 1 minute to analyze the handwritten samples and 1 minute to write. After one minute, go through the samples one by one and have each team verbally tell you their answer (e.g. It's John's.) Award 10 points for each correct answer the team gets.