From: Joel VanderWerf [mailto:vjoel / path.berkeley.edu] 
# arr.delete_at(arr.index(2))
# (Of course that's limited to #== comparisons. Maybe 
# Array#index should 
# take a block...)

of course, we agree, that is why matz put it in 1.9 ;)

irb(main):011:0> RUBY_VERSION
=> "1.9.0"
irb(main):012:0> a
=> ["this", "is", "a", "test"]
irb(main):013:0> a.index{|e| e=~ /^is/}
=> 1
irb(main):014:0> a
=> ["this", "is", "a", "test"]
irb(main):015:0> a.delete_at(a.index{|e| e=~ /^is/})
=> "is"
irb(main):016:0> a
=> ["this", "a", "test"]

and 1.9 is fast :)

kind regards -botp