Binaries in clusters are particularly important: If unevolved, they may provide a check of the mass predicted for the point on the cluster Isochrone where they are found. If mass-exchange has occurred, the age and chemical abundance inferred from other cluster stars provide useful boundary conditions for theoretical models of binary evolution involving mass exchange. With these goals in mind, we have studied the early-type (B2+B6), 3.7-day eclipsing binary BF Cen in the young cluster NGC 3766.