29. Chamilo After just 18 months in existence, this open source learning management system racked up half a million users. The website includes a helpful demo so that you can try the software out before downloading. Operating System: Windows, Linux, Unix, OS X
30. Canvas LMS The Canvas learning management system is designed to be as user-friendly as possible, with an intuitive interface and features like the SpeedGrader that help instructors save time. The software is also available on an SaaS basis from corporate sponsor Instructure. Operating System: Linux, Unix, OS X
31. RapidFTR
32. Dakar 2011
In this newer racing game, you drive in the Dakar rally through 14 different stages based on real maps. It includes six different vehicles and 140 different opponents. Operating System: Windows, Linux
33. Stunt Rally
Stunt Rally is also a racing game, and it offers 57 tracks, 9 scenarios and 8 cars. There's also a track editor, so you can create your own courses, complete with loops and curves. Operating System: Windows, Linux
This fork of the popular first-person shooter integrates some of the best features of Battlefield, Quake and Call of Duty into AssaultCube, while maintaining a lightweight footprint. Other improvements include ricochet shots, new weapons, improved radar and more. Operating System: Windows, Linux
35. Foobillard++
This is also a remake of an earlier open source game. Check out the screenshots on the site to see the excellent graphics for this billiards game. Operating System: Windows, Linux
36. WebP
Pronounced "weppy," WebP is Google's open source graphic file format alternative to jpeg. On average, WebP files are about 40 percent small than jpeg files. Operating System: OS Independent
37. OpenLayers
This alternative to Google Maps and Bing Maps provides free APIs that can put dynamic, JavaScript-based maps on any website. It's sponsored by the Open Source Geospatial Foundation. Operating System: OS Independent
38. Ultimate Calc
This scientific and graphing calculator solves complex equations and offers an easy-to-use interface. It supports plug-ins and scripts to extend its capabilities. Operating System: Windows
39. LISPmob This is an open source version of the LISP-Mobile Node implementation, which provides mobile devices greater ability to roam while remaining connected to the Internet. It was originally developed by Cisco and is now maintained by Barcelona Tech University. Operating System: Linux
This app turns your J2ME-enabled phone into a remote control for your PC. It controls most media players, PowerPoint, a remote keyboard and more. Operating System: Windows
41. Tizen
Still in the extremely early stages of development, Tizen is the mobile OS meant to replace Meego. Development is being led by Intel, Samsung and the Linux Foundation; a first release is expected in the first quarter of 2012. Operating System: N/A
42. LibreOffice
We admit, LibreOffice is far from unknwon, but it made the list because it's so new. This is the community fork of OpenOffice that offers MS Office-compatible word processing, spreadsheets, presentations and more. Operating System: Windows, Linux, OS X
43. ATHENA
Designed for cultural and arts organizations, ATHENA offers business management software with modules for ticket sales, accounting, donor and sponsor information, fundraising and marketing and more. The same software is available online with a subscription through Artful.ly. Operating System: Linux
44. Modelio
The code behind Modelio has actually been in development for more than 20 years, but parent company Modeliosoft just recently released it under an open source license. It offers a UML modeler, BPMN support, Java code generator, and support for XML, HTML and Jython. Operating System: Windows, Linux