To pass a block to a method you define the block after the method call with either the curly bracket enclosure {} or the do/end syntax. An example of passing a block to the each method of an array:

my_array.each {|a| puts a}

Any method in Ruby can take a block. You can explicitly add a block to a method by putting an ampersand & before the variable name in the method definition. An example of this would be:

def my_method(&my_block)
  my_block.call
end