App Engine JavaScript SDK

"App Engine for JavaScript! With App Engine, you can build web applications using the JavaScript programming language, and take advantage of the many libraries, tools and frameworks for JavaScript that professional developers use to build world-class web applications. Your JavaScript application runs on Google's scalable infrastructure on top of Java and Rhino, and uses large-scale persistent storage and services."

Recipe: CloudKit

"CloudKit is Jon Crosby’s neato web app that vends schemaless-but-versioned JSON objects via a RESTful web API."

objectify-appengine - Project Hosting on Google Code

"Objectify-Appengine provides the thinnest convenient layer which addresses these issues, yet preserves the elegance of get, put, delete, and query."

MongoDB

JSON key-value store

Using a Caching Proxy Server for Web Demos

Simple python caching proxy server: run your test once against the proxy server in 'record' mode, and then after that you can use the server for consistent local playback.

Super Awesome Buttons with CSS3 and RGBA

Mercurial: The Definitive Guide

Alternative Mercurial guide.

Hg Init: a Mercurial tutorial by Joel Spolsky

For when I want to actually learn a DVCS:

Mercurial is a modern, open source, distributed version control system, and a compelling upgrade from older systems like Subversion. In this user-friendly, six-part tutorial, Joel Spolsky teaches you the key concepts.

Gecko Memory Profiler

Add-on appears to be stuck at Firefox 3.5-only though.

Labs/Memory Profiler - MozillaWiki: "Memory Profiler is an experimental Labs project that attempts to make debugging memory use in web pages easier.

For more information about the tool's design and rationale, see Atul's blog post entitled Web Application Memory Profiling, Take Two."