Provide the ESRI maps that the City has and continues to develop. Provide the ESRI API's that they have developed.
Developers could them develop MASHUP apps. Example: A map that shows all road closures, reason for the road closure and impact such as bus re-route or trash pick up. This way the private sector and various government agencie and NGO's like the electric company can coordinate efforts for a one time only road closure.
Mashup Crime data with other mapping data such as where the overt surveylance cameras are located.
I'd like to combine this idea with