From the meditation -
"The guru, meaning spiritual teacher, and more literally translated as one who brings light into darkness (Sanskrit: GU (darkness) RU (light))—the one who reveals and embodies the light, can show us the way, correct our errors, and very importantly, acts as a role model...
A proper guru does not come out of nowhere. It is recommended that the guru be part of an established lineage. They should be learned in the scriptures of their tradition. Their life should be exemplary in its virtue. The true guru does not exploit followers financially, sexually or any other way.
Different traditions have different perspectives on the nature of the guru. He or she could be seen simply as a spiritual teacher. To some the guru is an enlightened being. Guru may mean the function of Self Revelation; so that the person who is a guru represents the nature of enlightenment—God-Realization, or a related idea."
As Bob Dylan sang you Gotta Serve Somebody, you might as well make it somebody who helps you on your path to joy, peace and enlightenment.
One of the nice things about the Interlude site is that it isn't centered on any single spiritual tradition - if you read through the prayers and meditations you'll see Buddhist, Hindu, Christian, Jewish and Islamic traditions incorporated in the writings.