M.U.L.E was an early economic computer game from way back in 1983. I remember playing it until my eyes bled, hands cramps, until Crystite pirates terrorized my waking dreams. The children of the original designer has brought back M.U.L.E as a free game playable solo or multiplayer.
Here is the slashdot story on the return of M.U.L.E , M.U.L.E. Is Back.
Planet Mule, site of the reborn M.U.L.E .