Phoenix Wright: Ace Attorney

Phoenix Wright really harkens back to the old-school graphic adventures (and even back to text adventures also).

The game has several cases, where you travel around to different sites to click around and investigate information and clues, before going to court and using that information you've found to find holes in the prosecution's case.
It's also just very wacky in the storyline, and they did a great job of incorporating characters throughout each case as you play through. The last case was designed specifically for the DS and so has much more use of the touch screen (for example, you "dust" for prints by dabbing dust all over the touchscreen with your stylus and then blowing it off through the DS's mic).
There's a sequel coming out in early 2007 I think.

At a party recently I met someone who is in law school to become a defense attorney, and wound up trying to explain this game - where you play as a defense attorney, Phoenix Wright.

It sounded like she was pretty entertained by it!

Played back in Sept.