I don't know Rails, and that may be why I hadn't heard of Rails Hotline before last week. If you're not a Rails dev and are also unfamiliar, it's pretty much what it sounds like: developers volunteer to take a shift answering the phone if anyone calls, and other developers can call in and ask their Rails questions of a real person, absent the distractions of IRC or typing in general. Though I rely on IRC pretty heavily when I run into questions, this made immediate sense to me, because sometimes I run into things I just don't have the words for, or I need a longer, more abstract explanation than is comfortable to type into a chat window.
If you don't want to contribute time, there's also a button on that main page to contribute money. ;) The service is free for the first two hours, but it'll take money to continue it after that.