  Four double-parton scattering processes are examined at the Fermilab Tevatron
energy. With optimized kinematical cuts and realistic parton level simulation
for both signals and backgrounds, we find large samples of four-jet and
three-jet+one-photon events with signal to background ratio being 20\%-30\%,
and much cleaner signals from two-jet+two-photon and two-jet+$e^+e^-$ final
states. The last channel may provide the first unambiguous observation of
multiple parton interactions, even with the existing data sample accumulated by
the Tevatron collider experiments.
