The phrase "parlor trick" refers to a simple and entertaining magic trick or stunt that is performed to impress and amuse people in a small gathering or social setting. Full definition
Even the corniest old gag is enriched by Andersson's unblinking gaze and densely detailed shots: when a joker at a family banquet insists on performing that old parlor trick of yanking the tablecloth out from under the dishes, he not only shatters a huge collection of crystal and china but also reveals a vintage table inlaid with swastikas. (chicagoreader.com)
... Going out and saying I'm going to cut a dividend, make a one - time buyback, these are sort of like parlor tricks, they aren't sustainable.» (reuters.com)
These bots essentially perform parlor tricks in which they respond with comments that are loosely related to a particular conversation, but they «can't say anything true about the real world.» (fortune.com)