  The STAR experiment at RHIC measures the longitudinal double-spin asymmetry
$A_{LL}$ for a variety of final states in collisions of longitudinally
polarized protons to constrain the polarized gluon distribution in the proton.
Asymmetries for mid-rapidity charged pion production benefit from large
cross-sections and the excellent tracking and particle identification
capabilities of the STAR Time Projection Chamber. This contribution presents a
measurement of the ratio of cross sections for inclusive $\pi^{-}$ and
$\pi^{+}$ production using data collected in 2005, as well as a new measurement
of $A_{LL}$ for charged pions opposite a jet obtained from the 2006 RHIC run.
