ThinBASIC Adventure Builder (a.k.a. T.A.B.) is a new FREE adventure creator project for Windows 98/2000/ME/XP/Vista/7 currently at Alpha stage and being developed with the thinbasic scripting language.

T.A.B. was created by Philip Richmond and operates on similar principles to 80’s popular retro adventure creators such as STAC, GAC, CAT, Quill or PAW.. It is being developed with the thinBASIC scripting language.
Sound and music supported: mp3, ogg, wav, aiff, mod.
Graphics supported: jpg, gif, bmp, png.

http://tab.thinbasic.com/ is the project home page. ScreenShots. Download the TAB Editor, the TAB Player and some games and demos. (3.6mb zip) There is also an email support group and discussion forum.

Some more info here: http://ifiction.wordpress.com/