Teen Agent
Teen Agent is a point and click graphic adventure, apparently this was the first Shareware graphic adventure. The shareware version of Teen Agent is only 10% of the full game, but there is still quite a lot to do.

You take the control of a teenager who has been hired by a secret organisation to find out why gold and cash has been dissapearing from banks. You are taken to a secret camp to being your training, the puzzles arn't too hard, and some of the script is quite funny, so it is quite a good game, but I think really its aimed at younger gamers. - Dean Hughes