  We present simulations of the motion of a single rigid rod in a disordered
static 2d-array of disk-like obstacles. The rotational, $D_{\rm R}$, and
center-of-mass translational, $D_{\rm CM}$, diffusion constants are calculated
for a wide range of rod length $L$ and density of obstacles $\rho$. It is found
that $D_{\rm CM}$ follows the behavior predicted by kinetic theory for a hard
disk with an effective radius $R(L)$. A dynamic crossover is observed in
$D_{\rm R}$ for $L$ comparable to the typical distance between neighboring
obstacles $d_{\rm nn}$. Using arguments from kinetic theory and reptation, we
rationalize the scaling laws, dynamic exponents, and prefactors observed for
$D_{\rm R}$. In analogy with the enhanced translational diffusion observed in
deeply supercooled liquids, the Stokes-Einstein-Debye relation is violated for
$L > 0.6d_{\rm nn}$.
