Here's a concept: take Brain Age and write a story to it. Level-5 did just that, creating Professor Layton for DS, a combination of classic brain teasers and an adventure-style narrative driven by irresistible Totoro-esque looks -- the celebrated developer even got a University professor to slap his seal of approval on it (but stopped short of making Prof. Akira Tago the game's antagonistic talking head).
The first game in the trilogy, Professor Layton and the Curious Mysterious Village, was released in Japan back in February (its sequel arrives this week, with the third game not far behind) and became the envy of westerners keen to the next Ouedan or Gyakuten Saiban breakout hit. Like those series (known as Elite Beat Agents and Phoenix Wright in the US), Professor Layton will be localized for western audiences. Today, we have the date: February 18th, 2008.
If you can navigate through the language barrier, there's a playable demo on the official Japanese site.