OpenLayers makes it easy to put a dynamic map in any web page. It can display map tiles and markers loaded from any source. OpenLayers has been developed to further the use of geographic information of all kinds. OpenLayers is completely free, Open Source JavaScript, released under the 2-clause BSD License (also known as the FreeBSD).

Leaflet is a modern, lightweight open-source JavaScript library for mobile-friendly interactive maps. It is developed by Vladimir Agafonkin of CloudMade with a team of dedicated contributors. Weighing just about 22 KB of gzipped JS code, it still has all the features most developers ever need for online maps, while providing a fast, pleasant user experience.

It is built from the ground up to work efficiently and smoothly on both desktop and mobile platforms like iOS and Android, taking advantage of HTML5 and CSS3 on modern browsers. The focus is on usability, performance, small size, A-grade browser support and an easy-to-use API with convention over configuration. The OOP-based code of the library is designed to be modular, extensible and very easy to understand.

Modest Maps is a small, extensible, and free library for designers and developers who want to use interactive maps in their own projects. It provides a core set of features in a tight, clean package with plenty of hooks for additional functionality.

We at StreetEasy decided to build our own maps using, among other tools, OpenStreetMap, TileMill, MapBox and Leaflet, instead of paying hundreds of thousands of dollars per year to Google. And yes, the money pushed us into doing it, but we're happier with the result because we now control the contents of our maps. (and now there is a follow up post too https://plus.google.com/118383351194421484817/posts/8x6xSQYypwt )

ODK Collect renders forms into a sequence of input prompts that apply form logic, entry constraints, and repeating sub-structures. Users work through the prompts and can save the submission at any point. Finalized submissions can be sent to (and new forms downloaded from) a server. Currently, ODK Collect uses the Android platform, supports a wide variety of prompts (text, number, location, multimedia, barcodes), and works well without network connectivity.

Open Data Kit (ODK) is a free and open-source set of tools which help organizations author, field, and manage mobile data collection solutions. ODK provides an out-of-the-box solution for users to:

• Build a data collection form or survey;
• Collect the data on a mobile device and send it to a server; and
• Aggregate the collected data on a server and extract it in useful formats.

In addition to socio-economic and health surveys with GPS locations and images, ODK is being used to create decision support for clinicians and for building multimedia-rich nature mapping tools. See the list available tools, featured deployments, and implementation companies for more examples of what the ODK community is doing. We welcome and encourage participation from the user community.

SickStache is an open source application to manage your SickBeard server.

Market: https://play.google.com/store/apps/details?id=org.sickstache&hl=en
Source and apk: https://code.google.com/p/sick-stashe/
License: GPLv3

Access your personal Ampache music cloud anywhere. Ampache.NET is a music player for the Ampache media server optimized for tablets and ICS

License: MIT
Sources: https://gitorious.org/ampache-net
Market: https://play.google.com/store/apps/details?id=johnmooreampachenet.johnmooreampachenet&hl=en

The fast, reliable way to make localhost part of the Web.

PageKite makes local websites or SSH servers publicly accessible in mere seconds, and works with any computer and any Internet connection.

It's also 100% Open Source.

Liberate your ideas - Write online, from anywhere, with your friends. Easily keep track of your documents instead of being tracked and trapped by the web's monopolies. We neither store your data nor track you. Libre Docs is only the application – your data is stored where you want it to be, using the open remoteStorage protocol.

"New Zealand electric racecar developer Greenstage is close to finishing an open source project called 'Tumanako,' which would allow owners of electric cars and motorcycles to tweak the code in their vehicles. Electric vehicle gearheads grouse about proprietary code that keeps current, torque and speed within very conservative limits. 'In racing, you need the system to push all those parameters to the limits. You only need the system to survive until just past the finish line,' says Bill Dube, the owner of the record-setting KillaCycle. Open source code could also be used to build any type of electric vehicle, from cars and submarines to motor-launched aerial gliders, from scratch. It's like Linux for your Chevy Volt."

OpenTBS is a plug-in for the TinyButStrong Template Engine.

TinyButStrong is a PHP Template Engine which has special template syntax and allows you to design templates in their natural editing tools. But it normally works only for Text files, including XML and HTML.

With TinyButStrong and its plug-in OpenTBS, you can use the template engine to merge OpenOffice documents and Ms Office documents with lot of facilities. All OpenDocument Format (ODF) and Office Open XML (OOXML) can be merged with OpenTBS, and also XPS files (XPS is a PDF competitor provided by Microsoft). In fact, all zip archives containing Xml/Html/Text files can be merged with OpenTBS.
What is special to OpenTBS:

Design your templates directly with OpenOffice or MS Office.
No exe file needed to merge documents.
No temporary files needed to merge documents.
Output directly as an http download, a new file on the disk, or as a string (for file attachment for example).
Works with both PHP 4 and PHP 5.
No PHP extension is required (If the Zlib extension is enabled it becomes easier to use templates, see more detail below)

You should know Template Engines and more specifically TinyButStrong to use OpenTBS.

I just found this project, which is described a.t.m as a learning project.

Is there a more serious, open source Bitcoin exchange? I'm aware exchanging BTC for fiat money can be quite complex, and might not fit an open source model, but an exchange specializing in crypto-currencies shouldn't be that complicated to setup, so I think there is room for an open source one.

Lately there has been quite some debate about “free services” and what they mean to their users. A lot of it started with the excellent article “Don’t be a free user” by Maciej Ceglowski which described a few unpleasant truths.

En discutant avec un collègue adepte de bicyclette je me suis rendu compte que cette ressource fantastique qu'est OpenCycleMap.org est vraiment méconnue!

Ces cartes utilisent les données d'OpenStreetMap, qui elles mêmes sont alimentées par des banques de données gouvernementales, par la communauté, et bien d'autres sources. Les données sont souvent plus précises que sur Google Maps mais surtout, elles sont libres de réutilisation.

Bonne route!

switch2osm.org explains how to make the switch – from first principles to technical how-tos.

ThinkUp is a free, open source web application that captures all your activity on social networks like Twitter, Facebook and Google+.

With ThinkUp, you can store your social activity in a database that you control, making it easy to search, sort, analyze, publish and display activity from your network. All you need is a web server that can run a PHP application.