Going along with another thread where i've posted about adventure games,
http://www.adventuregamestudio.co.uk is the official website of AGS, a freeware... well, adventure game studio. It is capable of creating any kind of 2D adventure game that you can think of, including games like Sierras classic AGI, SCI0, SCI1 and SCI32 style games, Lucasarts SCUMM style games, and so on with little to no programming knowledge neccesary, and you can also make other types of games if you know how to code (there has been a Zelda style RPG made, a platform game, a game which is very much like Cannon Fodder, and currently in the works, a game that is heavily inspired by the original Command and Conquer).
At the site, you can browse the games index which features about 100-200 free games ranging in size, whilst the forums at
http://www.bigbluecup.com/yabb/index.php are likely to have double that if you are patient and want to go through the completed games section of the forum.
If you don't know, 5 Days a Stranger, 7 Days a Skeptic and Cirque de Zale, available here at Abandonia were made with AGS (not sure if any other AGS games are here, haven't looked). If you liked them, then you'd be surprised to find that there are many more games that are rated better in the AGS community. You should all check it out.