If your students know these shows already then you can play up the "gameshow" aspect, act like a host or include sound effects. If they don't know the shows it doesn't matter, these are still good solid games for the classroom!
5. Countdown (wiki) A British gameshow where contestants attempt to make the longest word possible from a random selection of nine letters.
You need: Letters of the alphabet on magnetic cards
How to play: Make this a group activity so there is less pressure on the students. Randomly select alphabet cards (ensuring there are enough vowels) or have a student select for you. Put the cards up on the board and give the students a set time to find the longest word they can. Allow dictionaries for lower level classes. Award points for the longest words.
4. Blockbusters ( wiki ) Originally American but with a longer running British counterpart, contestants attempt to cross a board of hexagons which have letters on them by answering trivia questions.
You need: A board with hexagonal spaces, each space with a letter. Either print and photocopy to a large size or draw directly onto a board if you have time. You also need trivia questions where the answer begins with the letter on the hexagon. It's a good idea to have multiple questions in case no-one can answer.
How to play: The original game was for a solo contestant vs a pair of contestants. You can vary this depending on how your students are. It could be two large teams with students taking turns to answer, or you could have multiple rounds with smaller groups leading to a championship or you could make small desktop versions for small groups to play with one Question Master.
Assign one team to go from left to right and one team to go top to bottom. Choose a letter at random to start and assign that hexagon to the first student to answer. (colour it in or use small magnets) That student can then choose the next hexagon (must be touching the first) to try to win. NB In the TV show the contestant who chooses has a chance to answer the next question uninterrupted, however in the classroom it works much better if anyone can answer any question. The first team to make a "path" either left to right or top to bottom is the winner.
3. The Weakest Link (wiki) Originally British but with worldwide versions, players attempt to answer a chain of correct answers to win the most money possible.
You need: Lots of questions, a scoring grid of some kind on the board.
How to play: The original version is quite complicated and doesn't transfer well to the classroom but this is a version that I play in fairly well-behaved classes. Split the class into teams as you see fit, around six is good. Decide randomly which team will start. Ask them a question, if they can answer they get one mark/point/magnet on the board. They can then choose to "Stop" or "Play". If they stop then their point is safe, and you move to the next team. If they choose to play then you will ask them another question. If they cannot answer then they lose their point and you move to the next team. The first team to get to the top of the scoring grid (which is as big as your time allows) is the winner! To prevent the early teams winning too soon it's a good idea to have a limit on how many questions they can answer in a chain
2. Family Fortunes/Feud (wiki) Family groups compete to give the most popular answers to pre-surved questions.
You need: A set of questions such as "What is your favourite sport?". Ask all the teachers at your school or survey a different class of students to get the most popular answers. Write up these answers for your reference. Whiteboards/chalkboards/pads of paper for each team
How to Play: Split the class into teams, this depends on your class size but for a class of forty, ten groups is good. Instead of having one player at a time come up like the TV show, ask the question and have the teams write down what they think is the most popular answers. After a certain time have the students hold up their whiteboards and if they have any of the answers reveal those answers dramatically and award points (more points for more popular answers) if there are any unrevealed answers then have the students shout out what they think for bonus points.
1. Who Wants To Be A Millionaire? (wiki) Possibly the most well-know gameshow on this list, contestants must answers 15 questions to get to a million pounds/dollars etc
You need: multiple-choice trivia questions
How to Play: This is a simplified team version of the game. Split the class into teams. Each team gets a money grid to race up. Take turns asking each team a multiple choice question (but have them answer in full for English practice!). Allow each team a 50/50, Ask The Audience or Phone a Friend. These work best if you can prepare surveying another class for Ask The Audience and asking certain teachers for Phone a Friend. (if you can use photos of the teachers then the class really enjoys it)
These games are great for adding a bit of variety to your classes, some of them take more preparation than others but the students interest pays off! Good luck!