"She hopped a C-130 up to Chu Lai and stayed at the USO"
Public DomainUSO

The United Service Organizations (USO) started in the early 1900s as a "Home away from Home" for members of the military. During WWII it became widely popular and many Americans not serving volunteered to help provide USO services.

After the war it was disbanded, but was reinstated in the Korean War. During the Vietnam War, USO started to locate some of its bases in combat zones, providing entertainment and other services to members of the military.