Shiritori is a game that all of the students already know, but playing it as a relay is an exciting twist that never fails as a warm-up.
Do a brief review of how shiritori works in English. Usually for this part I write a word on the board (elephant) and have students call out suggestions for the next word (e.g. teacher).
Then put them into teams (I usually just use the rows they're already sitting in). Explain that one-by-one a student from each team will write one word on the board, and then they will use a piece of chalk as their baton to tap in the next student on their team.
I generally given each team a different starting letter so they can't easily copy words from other teams.
Set a timer for about 2 minutes to see which team can write the most words the fastest (spelled correctly, of course).
Play about two or three rounds and the students will be fully awake and ready for English class.
Of course, the classes love when I add more rules in subsequent rounds. For example, can't use their textbook, or no words with less than three letters, or, if two teams write the same word then they both lose a point.
This is a great warm up idea. Thank you for sharing.
Since it's holiday season now, it could be fun to give higher level students a category requirement (holidays, Christmas, winter, etc.)
I like doing this game too. It really helps awareness of the last letter of words. Of course it helps build vocab too. And I recall reading somewhere that Donald Keane played this Japanese version when he was studying Japanese with his classmates.