Many times, the students will want to get together again to play, and even start their own band. Tagging on to the last two concepts is the need for disinterested students to perform. I am not speaking about the good, old recital. To a student who is forced into lessons, a recital is the ultimate punishment. Find out what opportunities your students may have to perform at their schools.
Talent shows are common in many schools, and are very low pressure performance opportunities.
Playing for a music class is a great option, as well. Most public school music teachers would love the chance to show their classes that music can be fun outside of the classroom. There is no better encouragement than the applause of friends. If you can give your student one or two positive performance experiences, you will have a guitarist forever. After all, that's what it's all about.