From NintendoWiki, your source on Nintendo Information. By Fans, For Fans.
Nintendo Labo (ニンテンドーラボ Nintendō Rabo) is a line of cardboard toys that interact with Nintendo Switch in a variety of ways. The line was originally revealed in a video announcement trailer posted on January 17, 2018, as "a new interactive experience for Nintendo Switch". Primarily aimed at children, Labo kits consist of sheets of cardboard and other parts that must be assembled into a given model. The first Labo sets will be released in April 2018.
Each Nintendo Labo kit features sheets of cardboard to build into a variety of models, referred to as "Toy-Con". The kits feature a piece of compatible software that features instructions on how to build each model and games that use the models. The software also lets players view models of completed Toy-Con and examine in-depth how they function. The Toy-Con interact with the system by inserting the Joy-Con controllers and, in some cases, the Nintendo Switch console in select areas, using the console's features to play.