Multi-Mechanize is an open source framework for web performance and load testing. It allows you to run simultaneous python scripts to generate load (synthetic transactions) against a web site or web service.

In your scripts, you have the convenience of mechanize along with the power of the full Python programming language at your disposal. You programmatically create test scripts to simulate virtual user activity. Your scripts will then generate HTTP requests to intelligently navigate a web site or send requests to a web service.

Multi-Mechanize uses a multi-process, multi-threaded engine to replay your scripts and generate concurrent virtual users.

MPEG Streamclip is a powerful free video converter, player, editor for Mac and Windows. It can play many movie files, not only MPEGs; it can convert MPEG files between muxed/demuxed formats for authoring; it can encode movies to many formats, including iPod; it can cut, trim and join movies. MPEG Streamclip can also download videos from YouTube and Google by entering the page URL.

DOM Monster is a cross-platform, cross-browser bookmarklet that will analyze the DOM & other features of the page you're on, and give you its bill of health.

Arbor is a graph visualization library built with web workers and jQuery. Rather than trying to be an all-encompassing framework, arbor provides an efficient, force-directed layout algorithm plus abstractions for graph organization and screen refresh handling. It leaves the actual screen-drawing to you. This means you can use it with canvas, SVG, or even positioned HTML elements; whatever display approach is appropriate for your project and your performance needs. As a result, the code you write with it can be focused on the things that make your project unique – the graph data and your visual style – rather than spending time on the physics math that makes the layouts possible.