The games involve Larry's escapades as he attempts (and mostly fails) to convince a variety of young nubile women (rendered with increasing sophistication throughout the series) to have sex with him.
The games featured large amounts of tasteless humor in the style of a gross-out teen comedy.
Because of the nature of the games, they featured an age verification system, which consisted of a series of questions the authors reasoned only adults would know the answer to.
The first Larry game was originally released as a text only adventure called Softporn Adventure[?], but it's the graphical verion that made it known.
wikipedia.org dumped 2003-03-17 with terodump