Omri, best is to dig around the furum topics and look for unanswered posts start with Geting started with LANs discussion, Im sure you'll find something interesting, you may also go to cisco bug tools database and see problems and workaround resports, have them go over cisco security advisory reports . Something not to hard? hmmm... have them fully document your network, have them organize your comm rooms and data cable management, label cisco devices in comm rooms, have them lear how to making cat5 cables, crossover cables, role over cables.. etc..
Cisco tools and resources
http://www.cisco.com/en/US/support/tsd_most_requested_tools.html
Rgds
Jorge
Jorge Rodriguez