"ThinkPad" the first notebook computer form IBM went on sale in 1992. The name was borrowed from a notebook they already made -- a paper notebook.
In the 1920s, IBM's corporate slogan was "THINK!"
For inspiration, employees and customers were given paper notebooks with the word "THINK" embossed in the cover.
While on a coffee break, IBM researcher Denny Wainwright was inspired by the notepad and came up with the name for their notebook computer line, "ThinkPad". In fact, the idea for the notebook computer was first conceptualized on the paper inside one of the brown leatherette notepads.
In 2005, IBM sold the ThinkPad brand for approximately $1.75 billion. While they're not known for style, both IBM and Lenovo manufactured ThinkPads are renown for high quality and reliability.
[Source: Yahoo Answers blog]