Taobao is the Chinese equivalent of eBay. The most interesting project on the Taobao code website is TFS（Taobao FileSystem）.
It's a highly scalable, highly available, high performance Internet service-oriented distributed file system, the design objective is to support vast amounts of unstructured data.
Tair, similar to memcached, might also be interesting. It's a distributed, high performance key/value storage system. Not sure if there are any advantages
You can browse the code via the "source" - "browse" tabs, or just checkout the code via svn.
Taobao FileSystem open sourced
code.taobao.org