This document summarizes a presentation on metaprogramming in Ruby. It discusses: 1) What is metaprogramming - writing code that writes code. 2) Metaprogramming techniques in Ruby include opening classes at runtime to modify behavior, using dynamic dispatch to avoid duplication, and defining singleton methods to add methods to individual objects. 3) Ruby's busy runtime gives power for introspection and modification of language constructs at runtime, enabling techniques like metaprogramming. This allows the language to grow and be customized more easily.