Angular momentum will be conserved in a forming star system, but can be distributed among several channels: stellar rotation, binary orbits, protoplanetary disks, and planets themselves. Binaries in particular may have a strong effect on other properties of the system. For example, stars in binaries tend to rotate rapidly, but rarely host planets. Open star clusters include stars with a range of masses that all have the same age, and can serve as benchmarks for studying the evolution of stellar properties. I use open clusters determine how binary companions affect the evolution of stellar rotation, either by tidal forces or by disrupting disks around young stars. I will present new constraints on rotation for the roughly 700-million-year-old Hyades and Praesepe clusters, and preliminary results that indicate the limits of binary influence on protoplanetary disks.