In the 1960's Drive-ins were the all-American hangout for teenagers. Mel's Drive-In was a classic, widely remembered by anyone who grew up in the 1950s or 1960s in the San Francisco area. Mel's is the drive-in everyone recognises. HO scale, needs paint and glue for final assembly. HO or H0 is the most popular scale of model railway in the world and the scale of most slot car sets - about Hot Wheels size; 1:87 ratio.