My Cold War childhood was like an unending session of Soviet show-and-tell.
elementary school teaching tool, 1948, American English.
An elaborate display, usually for selling or other persuasion; dog and pony act: There just hasn't been time to arrange the kind of show-and-tell that attracts media attention/ No one seems to have been impressed by the show-and-tell
[1970s+; fr the name of an elementary-school teaching technique of the late 1940s where pupils exhibit and explain things]
A visual dataflow language designed for use by elementary school children.
["A Visual Language for Keyboardless Programming", T. Kimura et al, TR WUCS-86-6, CS Dept Washington U, Mar 1986].
["Show and Tell: A Visual Language", T.D. Kimura et al in Visual Programming Environments: Paradigms and Systems, E.P. Glinert ed, IEEE Comp Sci Press, 1990, pp. 397-404].