The Open Source Cluster Application Resources (OSCAR) is a cluster software stack providing a complete infrastructure for cluster computing. The OSCAR project started in April 2000 with its first public release a year later as a self-installing compilation of “best practices” for high-performance classic Beowulf cluster computing. Since its inception approximately three years ago, OSCAR has matured to include cluster installation, maintenance, and operation capabilities and as a result has become one of the most popular cluster computing packages worldwide. In the past year, OSCAR has begun to expand into other cluster paradigms including Thin OSCAR, a diskless cluster solution, and High-Availability OSCAR, embracing fault tolerant capabilities. This paper will cover the current status of OSCAR including its two latest invocations – Thin OSCAR and High-Availability OSCAR – as well as the details of the individual component technology used in the creation of OSCAR.