Mod: O.P. posted a referral link, and I have changed it to non-referral link. However if you are happy using O.P.'s referral link, click here.
Heroes on Newerth is celebrating their 1 year anniversary by having a play for free week (normally USD$30)
I have been playing this game for 6 months and in insanely addictive. There is quite a steep learning curve but the update two days ago has made the initiation a lot easier for the expected new player influx by providing guides and recommended hero builds in game.
If you ever played DOTA of LOL this is a great time to upgrade or give HoN a go for free or even try a new genre of game.
Also don't take it to heart if people rage at you for not knowing what your doing, once you get to your level in matchmaking or public games you will find it a lot more enjoyable.
Have Fun!!
EDIT: For those of you who are raging, it is a referral link. Here is a non referral one if you really don't want to be generous http://www.heroesofnewerth.com/trial.php
Also, the difference between this week and a trial is that trial accounts only allow you to play public games. this allows you full access to matchmaking and all other features.
Referral link? Tsk tsk..
How long is it "free" for? Do you have to start paying later?