Students build their own cell in small groups using everyday items that they happen to have with them that day!
I use this activity with my biology students. All three versions of the assignment are included in this PDF and they are differentiated according to ability level. They are in order of high to low ability.
All versions of the activity share the same objectives, core procedure, and what I like to call the "Core Four" analysis questions that every group must answer. The Core Four makes for a great whole group discussion opportunity post-activity.