Installing a CAS server
Yale CAS (http://www.jasig.org/cas) is a single sign-on server. It is designed as a campus-wide solution and as such is easy to install and relatively simple to configure to meet your specific infrastructural requirements. CAS allows you to sign in once and then automatically use lots of different applications without logging in again. This is made for much more pleasant user interaction across the range of applications used by a typical Jenkins user during their day.
Yale CAS has helper libraries in Java and PHP that makes integration of third-party applications straight-forward.
Yale CAS has also the significant advantage of having a pluggable set of handlers that authenticate across a range of backend servers such as LDAP, ...