Its the ultimate Myst Fan Game... based loosely on the URU storyline.
http://www.jumpingbeanstudios.com/dni
You have to have URU to finish the game - you simply will not be able to finish the 100+ puzzles without it. You also need at least a Dial up connection, however a broadband would be nice for the 50+ mb download.
Come join us on the 15th !
btw: Game Engine is off course Adventure Maker. But it also has unconventional use of the internet.