As reported by Mayank Gupta in dev chat:
06:03:11 PM) Mayank Gupta: Moodle Website Currently Unavailable?
(06:03:38 PM) Davo Smith: looks fine from here
(06:04:40 PM) sam marshall: confirmed, loading here too
(06:05:27 PM) Mayank Gupta: Its not working here (India) Getting this error message - Website Currently UnavailableThe website you are trying to access is currently unavailable. Please try again at a later time.If you are the site owner, review the following resource to help <http://www.cloudflare.com/wiki/I_keep_seeing_%22My_Site_is_Offline%22> resolve the issue.
(06:08:13 PM) Mayank Gupta: I checked it from another static IP - my windows based server, its opening fine there :0
(06:13:34 PM) sam marshall: jtomkinson was saying earlier how much it had reduced system usage... obviously that's by not letting people connect...
(06:13:44 PM) sam marshall: I think it may ban users based on IP range
(06:13:51 PM) sam marshall: but don't know in detail
(06:14:49 PM) Mayank Gupta: sam: yeah, I read that message too. But, it was working fine for me like 20 minutes back. Why did it block anyway?
(06:18:28 PM) Mayank Gupta: Let me just disconnect and reconnect again. Would give me a new IP lets see.
(06:26:35 PM) Mayank Gupta: Moodle.org is still unavailable for me. Thought its pinging fine ::
(06:37:49 PM) Mayank Gupta: No Helen, it did not ask me for a captcha. I just see this site unavailable page - http://awesomescreenshot.com/084uaac8a