It's at 72.18.130.89, but that won't get you far -- they seem to be running Apache multiheaded and haven't bothered with a default site for requests coming in by IP only.
I'm not seeing DNS for hackermonthly.com on my home ADSL2 connection (via Be Broadband), but my colo box (hosted by Bytemark) is resolving it fine. As I'm in the UK, this is definitely not Rogers in Canada -- it's some kind of DNS screw-up.
NB: It resolved okay via Be about 10 hours ago (10am BST) when I grabbed a copy this morning. I suspect something's come adrift since then.