Possible Cache Issue

example.sh

$ curl -v http://simpledesktops.com/api/desktop/random/
* About to connect() to simpledesktops.com port 80 (#0)
*   Trying 205.186.149.79... connected
* Connected to simpledesktops.com (205.186.149.79) port 80 (#0)
> GET /api/desktop/random/ HTTP/1.1
> User-Agent: curl/7.21.4 (universal-apple-darwin11.0) libcurl/7.21.4 OpenSSL/0.9.8r zlib/1.2.5
> Host: simpledesktops.com
> Accept: */*
> 
< HTTP/1.1 200 OK
< Date: Sat, 23 Jul 2011 21:54:28 GMT
< Content-Type: application/json; charset=utf-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Server: gunicorn/0.12.2
< Last-Modified: Sat, 23 Jul 2011 21:51:30 GMT
< Expires: Sat, 23 Jul 2011 22:01:30 GMT
< Vary: Authorization
< Cache-Control: max-age=600
< 
{
    "creator": {
        "url": "http://creativeinferno.com/", 
        "added": "2011-02-24 10:43:52", 
        "name": "Ben Hampton", 
        "email": "mindofblue@yahoo.com"
    }, 
    "previous_url": "/api/desktop/jack/", 
    "image": "desktops/2011/02/24/baseball.png", 
    "title": "Baseball Season", 
    "pk": 1624, 
    "image_url": "http://static.simpledesktops.com/desktops/2011/02/24/baseball.png", 
    "published": "2011-02-24 17:47:06", 
    "next_url": "/api/desktop/ducks-in-a-row/", 
    "slug": "baseball-season"
}
* Connection #0 to host simpledesktops.com left intact
* Closing connection #0