CVMFS is primarily used on the grid for distributing released experiment code, and it is expected that only a small number of people in each experiment manage that code. Fermilab has implemented a system for publishing temporary user analysis code in CVMFS, with repositories that are shared by many people and a server API that accepts tarballs from users in multiple experiments. Updates are expedited so they become available on worker nodes within a few minutes. The system is integrated with Fermilab's job submission system. This talk will describe the system and explain how it could be deployed at other sites and used by other job submission systems.