Command line JSON interpretation can be confusing. Python's json library (2.6+) provides a simple prettifier:

$ echo '{"json":"obj"}' | python -mjson.tool
{
    "json": "obj"
}

Or facetiously (from the obligatory Internet Chuck Norris Database):

$ curl -s "http://api.icndb.com/jokes/random?firstName=Andrew&lastName=Martin" | python -mjson.tool
{
    "type": "success",
    "value": {
        "categories": [
            "nerdy",
            "chuck norris"
        ],
        "id": 528,
        "joke": "Andrew Martin doesn't use GUI, he prefers COMMAND line."
    }
}

This can be wrapped in a handy shell function:

$ function parse_url_json() 
{
    curl -s "[email protected]" | python -mjson.tool
}

$ parse_url_json 'http://api.icndb.com/jokes/random?firstName=Andrew&lastName=Martin'

2.5 users can install the simplejson library.