Mahou Tsukai no Yoru
One of Nasu's earliest works, featuring Aozaki Aoko as the main character, rumor has it only a few TYPE-MOON members have read it. Some of the characters from the story were drawn by Takeuchi for his old personal website.
In April 2008, a game version of Mahou Ysukai no Yoru was announced as part of "the next worlds of TYPE-MOON." Unlike TYPE-MOON's previous games, Mahou Tsukiai no Yoru will not be an ero-game, and will feature Koyama Hirokazu as the lead artist in place of Takeuchi. The game was set to release sometime in 2009. After several delays, the game received a September 2010 release date. In September, however, TYPE-MOON announced that the release date has been pushed back to 2010 winter, and later TBA 2011.

Related
The Secret of Mahou Tsukai no Yoru's Birth - A special interview with Nasu Kinoko from TYPE-MOON Ace 2.
Tech Gian Mahou Tsukai no Yoru Questions and Answers - Part of a TYPE-MOON interview that appeared in the August 2010 issue of Tech Gian.
The next world of TYPE-MOON - An extended interview with TYPE-MOON on Mahou Tsukai no Yoru, Tsukihime remake, and Girls' Work that appeared in TYPE-MOON Ace.
TYPE-MOON Ace 4 Nasu Kinoko Interview - A brief interview with Nasu Kinoko that appeared in TYPE-MOON Ace 4, which was released on December 24th, 2009.
Rebirth of the Origin - A Mahou Tsukai no Yoru developer interview with Nasu Kinoko and Koyama Hirokazu from TYPE-MOON Ace 5, which was released on June 21st, 2010.