Movie marketing sure has changed. Studios rarely advertise films in newspapers today (assuming you can still find a newspaper today) but that medium was once the most effective method of promoting new films. Not only were traditional ads run but clever off-beat ancillary campaigns were also featured in the guise of entertainment. For example, here is a promotional campaign for the 1966 epic "Khartoum" starring Charlton Heston and Laurence Olivier that was squarely aimed at kids despite the fact that the intended audience was adults. This promotional block seen above was featured in the United Artists pressbook sent to American theater owners to suggest creative local publicity campaigns.
(For extensive coverage of the making of "Khartoum", get the Cinema Retro Movie Classic Roadshow Epics of the 1960s issue by clicking here.)