(Originally published in my book Brainstorming. Moscow: Manager, 2001. This is an updated version.)
Language Focus: Contrasting the present perfect and simple past tenses.
Level: Intermediate to advanced.
Format: Possible in pairs or small groups. Ideal as a whole class.
Objective: To talk about past experiences and decide who is telling the truth and who is bluffing.
STEP 1: Define bluff. You might allude to the bluffing done in poker games.
STEP 2: Select one student to be in the “hot seat”. This student will answer his/ her classmates’ questions about a past experience. Ask another student to begin the questioning. The first question uses the present perfect tense and must begin with “Have you ever…?” (= general past experience) The answer to this first question must be: “Yes, I have.”
NOTE: Students should ask about unusual but possible past experiences: “Have you ever gone sky diving?” – or – “Have you ever met someone famous?”
STEP 3: The class may then start calling out additional questions to learn details (= specific past events). These questions will all be in the simple past tense: “Where did you go sky diving? Who jumped with you?” Etc. Set a limit on the number of questions or the time allotted for questioning. (For example, one question per student or one minute of questioning by the entire class.)
STEP 4: Ask the students to decide collectively if the person in the “hot seat” is bluffing. As the student tells the truth, encourage the use of the present perfect tense: “Yes, I’ve really gone sky diving. I’ve done it twice.” – or – “No, I’ve never met anyone famous.”
STEP 5: Select a new person to be in the “hot seat”.
SUGGESTION: Lower level students may need more prompts to form questions. You can write a list of phrases on the board. (Examples: see a UFO, eat snake meat, ride a horse, cut someone’s hair) Let students choose from the list. Write the phrases using the base verb so that students gain practice in forming the present perfect.
English with Jennifer 
But you expect your students to have a lot of imagination. Aren’t most students very passive ? They expect an English class to be similar to any other class where the teacher preaches and the students dose. Can you really depart from this “format” your way?
When it comes to participating in a communicative activity, I think there are more factors involved than just the given student’s nature. For example, how you present a new activity can excite or turn off the students. Too much or too little enthusiasm can make students resistant. Also, I feel that the classroom atmosphere is something you need to develop much like you do the relationship with your students. They not only have to learn the language, but they can learn to learn. Teach them to take risks. Teach them it’s okay to make mistakes. Teach them it’s safe in your classroom to express unusual thoughts. If they have confidence in themselves and trust you as a teacher, I think they’ll be willing to try new activities.
Tip: Break down a challening activity into more steps and/ or provide plenty of prompts. As the students’ performance becomes more solid, decrease the support and push them towards more independent thinking and speaking.
Let me also add that I believe in the power of “teacher presence”. Call it energy. Call it attitude. Call it what you will. The teacher across the hall may be droning on in front of a class with glazed eyes, but you can be interacting with your students and really making the learning process a shared experience. Get them excited about learning (and I’m enough of a realist to admit that you may not be able to inspire every student you encounter in your career), and you just may be able to influence your colleague across the hall as well.
Thank you for your lessons, I really need to improve my English
You are most welcome, Stella. Feel free to post question on my forum. I also have Study Tips.
http://www.englishwithjennifer.com/forum2/
http://www.englishwithjennifer.com/study_tips_new.php
Regards!