First steps to getting census data and looking at example python parsing of it with gdal.
Testing the shp processing on DC:

 python census_shp.py ~/own/gis/census/temp/*shp dummy
test  /home/lwalter/own/gis/census/temp/tabblock2010_11_pophu.shp dummy
1/6507 (0.02%)
population  61
1001/6507 (15.38%)
population  127
2001/6507 (30.75%)
population  104
3001/6507 (46.12%)
population  0
4001/6507 (61.49%)
population  408
5001/6507 (76.86%)
population  299
6001/6507 (92.22%)
population  0
Getting overall bounding box for entire fips region.
Get bounding population, total population
Next put all the geoms and population numbers into a datastructure, then process it again and plot the geoms to screen with colorized population using pygame to draw with.