Abstract: Elastomeric interpolymers comprising at least two, or more, cyclic olefin monomers that are prepared by ring opening metathesis polymerization, and that are characterized by having no crystallinity, a glass transition temperature (Tg) of less than ?80° C., and a number average molecular weight (Mn) of at least 40 kg/mole, and functionalized products thereof. A ring opening metathesis polymerization process for producing the elastomeric interpolymers having no crystallinity. Uses of the elastomeric interpolymers in applications such as rubber compounds, tires, and the like. Cores of golf balls that are prepared by using metathesis polymerization produced elastomeric interpolymers having 0 to about 30% crystallinity.