The brand spankin' new Adobe Open Source Media Framework (OSMF) is an amazingly powerful code library that can significantly assist your Flash development.
Just as Flex is a framework that supports and standardizes application-centric Flash, OSMF supports and standardizes your media-centric Flash experiences (which, when you actually think about it, is basically all non-application experiences in Flash).
OSMF was born from a desire to standardize Flash video players. Have you ever noticed that no two video players in Flash are built the same way? That makes it really hard to maintain and monetize your work. It means that you literally have to recreate the wheel (or the video player, or the image gallery, or whatever) each time! That's a tremendous waste.
Although perhaps most directly relevant to video players, OSMF actually adds value to any AS3/Flash Player 10+ project. With standards and definitions for advanced media handling (audio, video, text, SWF, bitmap -- all of it), layouts, playlists, plug-ins and even monetization, OSMF makes it much easier and faster for you to create media-based Flash work, to use open-source plug-ins to further assist your work, and for you to maintain that work over time, and integrate it into other projects.
In short, if you're sick of wasting time re-creating the wheel with each AS3 project, OSMF is for you.
Come learn how to get started with OSMF, and watch R as he builds a powerful, standards-driven experience, in front of you in under an hour.