  We present the leading unpolarized and single spin asymmetries in inclusive
two-hadron production in electron-positron annihilation at the Z pole. The
azimuthal dependence in the unpolarized differential cross section of almost
back-to-back hadrons is a leading cos(2 phi) asymmetry, which arises solely due
to the intrinsic transverse momenta of the quarks. An extensive discussion on
how to measure this asymmetry and the accompanying time-reversal odd
fragmentation functions is given. A simple estimate indicates that the
asymmetry could be of the order of a percent.
