Eddy Bruel details how objects are implemented internally in SpiderMonkey as shape trees and slot vectors. This is done in order to minimize the memory footprint and obtain better JIT optimization with inline caching.
Guilherme Ottoni presents the design, implementation, and an evaluation of the HipHop compiler for PHP.
David Nolen unveils optimization techniques behind ClojureScript: code size, expression-oriented semantics, numerics, operations on JS primitive types, persistent data structures, etc.
Lars Bak presents several language virtual machines (Self, Strongtalk, Hotspot), why they matter and how they influenced V8 and Dart. His talk is centered on performance.
Dan North and Chris Read discuss techniques for implementing Agile Operations, a combination of Lean thinking and Agile development meant to optimize the business processes in order to reduce waste.
Hamlet D'Arcy explains the Lean principles - Eliminate Waste, Build Quality In, Create Knowledge, Defer Commitment, Deliver Fast, Respect People, Optimize the Whole – in the context of using Groovy as programming language.