It all depends on what you define as a network admin and where you work. I am a network admin, and I work at a school. My daily tasks include checking backups, filling up the photocopiers in the staff room with paper. Check helpdesk for any logged tickets. Attend to those and any other issues. After all that, read, research and try to experiment slightly with various things that could make the life of myself and my colleague easier.
Schools pose unique challenges I think, due to limited budget and unique cultures inside them. You are unlikely to work with any major Cisco equipment, but you are likely to get pounded with support queries and other bizarre issues.