Laptops, PC's that let lazy people be even lazier. They're made for mobility aspect, but are mostly used as a computer you can use while on the couch-or lying down. Because sitting down to Google "Tentacle rape" is really just over achieving.
One day, many years ago, an engineer looked at his computer and thought, "Gee, I wish I could carry it with me." A few years, a bit of development and a lot of pointing and laughing at the nerd later, the laptop was born.
All the inconvenience of a desktop system, at twice the expense, in a fragile plastic case that chips if you frown at it, laptops didn't really take off until the advent of wi-fi and mobile internet.