Hmm:

    rpav@central:~% ruby -v
    ruby 1.8.2 (2004-12-25) [i686-linux]
    rpav@central:~% irb    
    irb(main):001:0> "%s" % ["abc", "def"]
    => "abc"
    rpav@central:~% irb
    irb(main):001:0> $VERBOSE=1
    => 1
    irb(main):002:0> "%s" % ["abc", "def"]
    ArgumentError: too many arguments for format string
            from (irb):2:in `%'
            from (irb):2
    

Should $VERBOSE really break code?  Perhaps this should be rb_warn?
(sprintf.c:778)

-- 
Ryan Pavlik <rpav / mephle.com>