jeffwb, from a Greek font:
      _  _  _   _
     | || || |_| |_
     | \| |/ /     \
      \_   _( (| |) )
        | |  \_   _/
        |_|    |_|

davidh, in psiphi's signature:
      L_T_J .-I-,  Psi Phi:
        I   `-I-'  Science Fiction's Last, Best Hope

petercj, as a suggestion to psiphi's signature:
      \_I_/ .-I-,  Psi Phi:
        I   `-I-'  Science Fiction's Last, Best Hope

davidh, in a text version of one of our fliers.
            ___      _____      ___              _____
           (   \    (     )    /   )            (     )
            \   I    I   I    I   /           ___I   I___
             I  I    I   I    I  I        _-~~___     ___~~-_
             I   \___J   L___/   I       /  ,~   I   I   ~,  \
              \______     ______/       (  (     I   I     )  )
                     I   I               \_ `-___I   I___-' _/
                     I   I                 ~--___     ___--~
                     I   I                       I   I
             ____   (_____)            ____    _(_____)
            I __ \                    I __ \  I I
            I L_) )  ____   ()        I L_) ) I I__    ()
            I  __/  / ___)  ,I        I  __/  I  _ \   ,I
            I I     \___ \  II        I I     I I I I  II
            I_I     (____/  LJ        I_I     I_I I_I  LJ