A fun way to drill grammar structures or vocabulary items.

Age level - Any
Proficiency level - High beginners and above
Material - NONE
Objective -  This activity can be used both as a warmer or as a vocabulary/grammar review.

Tell your students you would like to invite them for a picnic, but they have to take just the right item in order to be allowed to participate. To discover what they should take, they need to pay attention to your clues. 
You will be the one who decides on the criterion for accepting or not the guests. For example, you can decide, WITHOUT TELLING ANYONE, that you will only want red (or yellow, or green,) food, or only fruit, only drinks, only industrialized food, or natural food, etc. This decision will depend on your objective and on the items you want to practice. 
An example: let's suppose that the item to be taken has to start with the first letter of the student's first name. The dialog will sound like this:
Thelma: I'm going to the picnic and I'm taking tomatoes. Amanda, what are you taking? 
Amanda: I'm taking bananas. 
Thelma: Sorry, Amanda. You won't be able to go... next! 
Brenda: I'm going to the picnic and I'm taking candy.
Thelma: Sorry, but you won't be able to go, either...

This will go on until a student (accidentally or not) gets the right answer. Then you should emphasize his/her name and the item:
Thelma: Yes, Paula, you are going and taking potatoes!!!
In our experience, students will want to go on and on until they discover the clue, so save some extra time for the activity!

VARIATION - If you want to practice different verb tenses, just change the initial sentence and model it with your group: 
  • Last Saturday, I went to a picnic and I took....
  • Next weekend, I'm going to go (will go, may go) to a picnic and I'm going to (I'll, may) take....
Instead of taking something, students can WEAR something, in case they are learning clothing items.