Skill challenges in a city

[MadDanEccles]

Hello;

I just wanted to say hi. I haven't played D&D in years, but my wife recently picked up the 4e books and we love it. My 8 year old daughter plays with us in the Keep on the Shadowfell campaign.

I am also working on a 2 character adventure based in a city. I'm thinking of something like D&D Noir. I have the basic plot, and a couple of encounters worked up, but I would like the adventure to be more solving puzzles and chasing down the perpetrators than one fight after another. Does anyone have any ideas of puzzles and hazards that would be appropriate for a city?

Thanks in advance for any hints