http://www.tefl.net/forums/viewtopic.php?f=5&t=1039 I don't have teaching experience but I would suggest mini games and then you can have rules that they "must look under the stool" but "mustn't touch the legs". They "must draw a picture of a lion" but "mustn't use the colour yellow". I don't know the age group of your students but I hope the article or I helped in any way, good luck! http://iteslj.org/games/ Here are games used for teaching. http://www.englishclub.com/grammar/verbs-modals-have-to-must-not-quiz.htm http://www.miguelmllop.com/practice/intermediate/verbtenses/must.htm http://s.mound.free.fr/skyblues67/modals/mustn%27t.htm http://www.quia.com/cb/380177.html I found this game interesting. You watch a video of what a female teacher had to do e.g. "she must scrub the floors..." then there is an interactive game (also in hmtl) which lets the students pick how many points they want to earn by answering the questions. It's a 1 - 2 player game. Sorry I couldn't find a video but I hope this helps you somehow.