A number of departments within the RU together bought a network-license for the concurrent use (by a small number of people) of Mathematica. If a department contributes to the payment of the license, one can borrow the installation CDs of Mathematica from C&CZ system administration.
The current version is 6, with CDs for Windows, Linux, Macintosh OSX and Unix (2 CDs). The CDs can be used for network as well as standalone installation. Older versions (5.2, 5.1.1, 5.1, 5.0.1, 5.0, 4.2, 4.1, 3.0) are available too. The Mathematica Book, 5th edition can be viewed at C&CZ.
The use of Mathematica is logged by the license-server. If a department regularly uses Mathematica without having participated in the license, one can contact Kees Keijzers.
On the Suns and Linux PCs that are managed by C&CZ, Mathematica can be found in the standard searchpath. On MS-Windows PCs Mathematica can be found on the S-disk (winxp-software).