I love tongue twisters. I think they are great for pronunciation practice, for spelling practice and they are so fun to work with, especially when you have to do those boring drills. So here's an activity that is great for pronunciation and spelling practice for learners of any age and proficiency level.
First you have to choose some tongue twisters you want to work with. I found the best collection here and here. Print them out and tell your students to form pairs or small groups (3-4 people). Give each group or pair a different tongue twister and tell them to learn it by heart.
Give them some time for that and then each pair or group should chant the tongue twister in unison over and over again while the rest of the class tries to write down what they are saying. The important thing is for the group who is "performing" not to stop at the end of the tongue twister, but to repeat it over and over again without a pause. They can stop only when someone from the class has written down the whole tongue twister (the person should signal it by raising their hand).
Once you check whether the tongue twister is guessed right, you choose another pair or group to chant their one (usually the one from which a person got the tongue twister right first).
Hope you have fun with this activity! :)