Experiments are described that introduce students to the important concepts of host-guest chemistry and size exclusion in porous metal-organic frameworks (MOFs). The experiment has been successfully carried out in both introductory and advanced-level inorganic chemistry laboratories. Students synthesized the porous MOF, alpha-Mg[subscript 3](O[subscript 2]CH)[subscript 6], and examined its ability to take up a variety of small organic molecules into its pores using [superscript 1]H NMR spectroscopy. The MOF exhibited size exclusion and students rationalized this behavior based on the structures of the organic molecules and the pore size of the MOF. (Contains 1 figure and 1 scheme.)