Projected 3D light as an attraction
Light can be an effective tool to draw a crowd. Projection of 3D light would amaze a huge crowd. Just such an idea from Vilnius, Lithuania (aerial map), would be perfect in St. Louis:
httpv://www.youtube.com/watch?v=UtuW1S0M7aY
Direct link to video on YouTube
We have many places downtown that would make ideal subjects for such a light show.
Old Court House:
Old Post Office:
Civil Courts:

Soldiers Memorial:
Hat tip to Michelle Swatek, Executive Director of AIA St. Louis, for bring this concept to my attention.
– Steve Patterson
While on a low tech scale, the Light Project near Grand Center in fall 2008 brought a fair amount of people out at night. Nothing like seeing tacky colored lamp shades hung from the ruins of a burnt out church. It was neat to see.
Also low tech, Denver's been lighting up their City & County Building for the holidays for many, many years (http://www.thedenverchannel.com/slideshow/news/…). While originally paid for out of the city budget, it's now funded by a private foundation. Which gets back to doing something here – who's going to pay for it? The folks who did City Garden? What they did in Vilnius is pretty cool, rivalling what you see on many major concert tours these days, but it doesn't come cheap . . .
Wow Steve, this idea is mezmerizing. I like the interplay using depth in unexpected ways, itself a tribute to the archetecture. The playful nature of this animation helps out, although i'm sure the scale make this idea even more impressive in real life.
I also appreciate the landmarks you picked, since they are under utilized resources that deserve more attention from both visitors and locals alike.