How does one get a DOTA 2 beta invite?

Try this

http://www.dota2.com/survey/experience/?l=english

Make some friends.

Alienwarearena gets 2000 Dota 2 Beta keys each month sign up for an account on there and get a free one takes like 5 mins

Apparently people get them by flooding this site with SteelSeries referrals.

isn't dota 2 free ?

Try one of these you might get lucky

if you really want it: buy an invite: 25€ each. Comes also with in-game stuff.

give much time and learn the game after u get invite.
Then you will know the real fun of multiplayer game :)

Love gaben more, he will give you

dance around a campfire while wearing a too-too

If you really want it, you should try on SteamTrades. You can get Dota for a cheap ($7) game or for 2-3 Dota/Team Fortress treasure keys (2$ each).
If you have never played a MOBA (like League of Legends or Heroes of Newerth - or the first Dota), Dota 2 will probably be A LOT hard for you. You should play with bots (or people you know) to understand how the game works, which hero suits you better, which items you have to buy etc., otherwise you'll most likely die every 3 minutes online and your team will insult you for feeding the other team :P

Enter steam store, search for Dota2, download... Already avaible.

One can trade for it. I traded some TF2 items for it.

As for my opinion, not my kind of game.

Okies cool. Will probably do steam trades for it.

Friend gives you an invite !!! like how i got it.