Problem:
mongoimport does not support JSON with the ISODate representation, for example

{ "_id" : ObjectId("4e5bb37258200ed9aabc5d67"), "name" : "Bob", "age" : 28, "address" : "123 fake street", "ts" : ISODate("2010-09-28T13:07:12Z") }

It will fail with the following error

Mon Apr 9 09:06:09 Assertion: 10340:Failure parsing JSON string near: , "ts" : I

Solution:
Extend monogimport to support ISODate

Test case:

> db.foo.save(

{name:"bob", ts: ISODate("2012-04-09")}

);

> db.foo.find(

{name:"bob"}

);

{ "_id" : ObjectId("4f82992047a6783d6427f207"), "name" : "bob", "ts" : ISODate("2012-04-09T00:00:00Z") }

> exit

cut & paste that object into a file , e.g. tmp/3/json

$ mongoimport -d test -c foo /tmp/3.json