Many laptop computers have composite TV output capability built into it. Another point to keep in mind. Always search for ways to actively involve your class with the one computer. A computer show run by you or one student is not going to get the job done. You need to come up with ways to involve all of the students.
Competition is usually a great way to make the participation happen.
Games and competition get students involved. The results of this competition need to be visible somewhere in the school setting. Students need to feel proud of their accomplishments. Accountability needs to be an ingredient. Students need to realize that they have responsibility for the activities with the computer.