I helped register a 5 person company in Libertyville, Illinois. They had a fabulous internal audit system.
On the last Friday of each month, They would audit two sections over lunch. All five were trained as auditors. As he audits began, four auditors would audit the applicable auditee and then four would audit a different auditee. As you can imagine the size of the company was small, and if documents were needed they were easy to obtain.
The company paid for a variety of lunches chosen by the auditees. It is a great program! And successful!
dave