Do you know what you mean when you ask for a challenge? What does challenging really mean?.
The thing about challenge is that it needs to come from within, too. We own much of the responsibility for creating challenges in our career. Stay with any job long enough and the job itself will stop being challenging. Keep doing the same tasks the same way and you’re going to get bored. Does that mean it’s time to start job-hunting? Maybe, but not necessarily.
If you’re monitoring the same servers every day, think about how you can automate part or all of the process. If you’ve got a process you’ve honed and refined, consider how you can improve it. That might mean scrapping it altogether and approaching it from a fresh angle. Get a certification. Learn a new language. Develop a training class for your colleagues or end-users. Organize and lead a regular forum for knowledge-sharing in your organization.