Fix a typo in the name of the latest til file.

ruby/passing-arbitrary-methods-as-blocks.md

@@ -0,0 +1,15 @@
+# Passing Arbitrary Methods As Blocks
+
+Use
+[`Object#method`](http://ruby-doc.org/core-1.8.7/Object.html#method-i-method)
+to create a callable `Method` object that can be passed to methods
+that yield to a block.
+
+```ruby
+def inc(x)
+  x + 1
+end
+
+[1,2,3].map(&method(:inc))
+#=> [2,3,4]
+```