  We consider longitudinal, parity-violating single-spin asymmetries in
proton-proton collisions at RHIC. The focus of this study is on the production
of single-inclusive jets, as well as on jets that contain a charm quark. While
the asymmetry for inclusive jets turns out to be small, we find considerably
larger effects for the case of charm production. We also investigate the role
of leading threshold logarithms and find that they increase the polarized and
unpolarized cross sections and reduce the spin asymmetry.
