For younger students I would do things like chromatography experiments, extraction of DNA and investigation of muscle by heart dissections etc. For older students that wanted to use some of the technology that we have available in the lab I would help them to take white blood cells out of tissue samples and label some of these up using fluorescently tagged antibodies. These can then be sorted through a machine called a FACS based on their fluorescence and students could then analyse how many of each sort of cell (T cell, B cell, macrophage etc) were present in the sample. We could even go further and take cells from different tissues or treat them with different drugs to look for differences!
What kind of thing would you think was interesting? I am up for suggestions!!! 🙂