Coffee cup calorimetry, performed with calorimeters made with styrofoam coffee cups, is a familiar experiment in the general chemistry laboratory. These calorimeters are inexpensive, easy to use, and provide good insulation for most thermodynamics experiments. This paper presents the successful substitution of paper coffee cups for styrofoam cups to construct homemade calorimeters. Important modifications to the experimental protocol when using paper cup calorimeters are discussed. Data collected using calorimeters constructed from the two types of cups are presented in order to demonstrate that comparable results can be obtained for the enthalpy of neutralization of an acid-base reaction and for the heat capacities of metals. These results also compare favorably with published values. Finally, an approach to using scientific literature to help general chemistry students examine whether paper or styrofoam cups provide the "greener" option is discussed.