Dota 2 - My nephew plays HoN and enjoys it quite a bit, so I want to try a MOBA. I want to try this out but I get the feeling I'm going to be completely clueless on how to play it and wind up sucking hind tit every game. Is there a match-making system that gets all the clueless players into the same game so they can fuck up without screwing up experienced players?
There are a few quick starter guides that will help acclimate you to the basics of gameplay and heroes--like
How To Play Dota 2 in 4 Minutes or
Dota Cinema's 2-3 minute long character-specific guides--but nothing will replace practice. Play in bot matches on your own and try out a few different heroes after looking at guides of characters you think you might be into. If you've got an experienced friend, try playing in coop bot matches with them. Once you're kind of familiar with gameplay basics and a few heroes you think you like, dive in to coop bot matches and try playing with others against a team of bots. If you go into a public match, at least somewhat prepared, you'll find your teammates to be more receptive or helpful if they perceive that you at least kind of know what doing and aren't just mashign your keyboard.
Have a mic. Use it. At the very least use text to communicate.
I would recommend trying a ranged/support hero since they're strictly level based, you just have to stay where the action is and not worry about last hits since supports don't really require gold or gear to be helpful to their team. If you buy a courier and ward, at least at round start, you'll immediately have thankful, friendly teammates. If you assist in ganks, even more gratitude.
Ultimately you'll want to probably try out each hero at least once. You will want to know who might face and what they are capable of. Also you never know which hero may appeal to you until you play them. But support is probably a good place to start.
Edit: I understand that there's a lot of information to digest and that's intimidating, at first. However, once the game starts to click that's what you love about it, that there's some much to learn.