IBM used to run the mainframe challenge, in which they let you play with one. It was more a PR exercise than a competition - <a href="http:&#x2F;&#x2F;www-05.ibm.com&#x2F;employment&#x2F;uk&#x2F;graduate-programmes&#x2F;mainframe&#x2F;index.shtml" rel="nofollow">http:&#x2F;&#x2F;www-05.ibm.com&#x2F;employment&#x2F;uk&#x2F;graduate-programmes&#x2F;main...</a>