gistfile1.txt

#!/bin/sh
curl -s http://www.a2dda.org/map/AADDACount.json | \
jq '.countdata[] | \
    { timestamp: (.timestamp | strptime("%m/%d/%Y %I:%M:%S %p")| mktime | todate), \
      facility: .facility, \
      spacesavail: (.spacesavail | tonumber) }' | \
mongoimport -d test -c a2dda

db.a2dda.aggregate( [ { $group: { _id: "$timestamp", total: { $sum: "$spacesavail" } } } ] )

db.a2dda.aggregate( [ { $group: { _id: "$timestamp", total: { $sum: "$spacesavail" } } }, { $sort: { _id: 1 } } ] )

ok, it's in crontab, let's let it run for a while