Eric D. Snider  Seven Psychopaths  Onscreen titles identify
which characters in "Seven Psychopaths" are the official seven
psychopaths, but the selection is arbitrary. Irish playwright-
turned-filmmaker Martin McDonagh ("In Bruges") has populated
this violently funny, self-referential tale of criminals and
wannabes with enough nutcases to fill a dozen psych wards.  And
what fun lunatics they are! McDonagh's surrogate, an Irish
screenwriter named Marty (Colin Farrell) who's trying to break
into Hollywood, is probably the sanest one here, though he
counters this with heavy, consistent drinking. Stuck with a
title for his next project -- "Seven Psychopaths" -- and little
else, he reluctantly takes story ideas from his friend Billy
(Sam Rockwell), a good-time guy and fledgling actor whose wild
temperament has been a hindrance in his career. ("I didn't mean
to break his nose," he says of a director he auditioned for.
"His nose just happened to be in the middle of where I was
punching.")  Some of Billy's loopiest id