Elastic properties of a variety of structures, such as polymers, noble element solids, and solids with very unharmonic interatomic potentials, are dominated by the shape and volume dependence of the entropy. The suggested tethered solid model consists of a periodic array of atoms that interact via potentials with infinite barriers. The potential energy of the system vanishes identically, and its properties are determined by the entropy. Elastic moduli of the solid are strictly proportional to the temperature. The model is used to test some approximate approaches to the problem of entropic elasticity, as well as a toy example of emergence of a harmonic response from unharmonic forces.