This project is always a hit with students, and it is how I finish up our unit on Ecology and Taxonomy. I give a final assessment as well, but this project alone, with the accompanying reflection questions, could serve as a final assessment.
For this project you will need to assemble a few materials and make a trip to a pet store to buy some crickets (they have them for feeding other pets). If you do not have access to a natural area with bark and leaves and stones and sticks, you will have to consider what your students could use instead. You can have students collect soil for the bottom of their terrariums, but some years I have found it easier to buy a bag of potting soil to share with the students.
For my class, I allow the students to collect a few materials from outside to use to improve the cricket habitat in their terrariums. Know that each student will collect enough to fill ten terrariums if you do not limit them, and then they will have trouble fitting things into their containers. Also know that if their containers are too full, they will not be able to find their crickets to observe them.
Before beginning this activity, have each student bring in a clear plastic container from home. Two-liter soda bottles work well, but larger containers are also fine. If students are able to bring more than one container, that is helpful, as there will be students who forget, or do not have access to an appropriate container.
Another item I like to have on hand, but it is not mandatory, is some small seeds to plant in the terrariums. Grass seed (annual rye, especially, because it sprouts in just a couple days) and perhaps alfalfa seeds are a good food source and give visual interest to the terrariums. Be careful not to plant too much or the sprouts will fill the available space. The crickets don't mind, I suspect, but this also makes it hard to find them.
Know that the crickets do chirp, and if they escape in your room, they will be chirping when you wish they wouldn't. Crickets can live for many weeks, and they will breed if given the opportunity and even marginal conditions. It is possible to tell the males from females, if you would like to breed them, and instructions are easily found online.