This is one of the coolest online blackjack concepts I've seen. This game uses the semi-anonymous currency BitCoins to play, and claims to be able to prove that it is dealing a fair game. The concept sounds valid to me, although I haven't researched enough to be able to validate the claim. The principle is simple enough and sounds solid.
See details at https://bitjack21.com/
For more on BitCoins, see here: http://www.bitcoin.org/
It would seem that this addresses both of the common online gambling concerns:
1) Is the game fairly dealt? Guaranteed so, if the concept is as described.
2) Will I get paid? I assume that your winning bitcoins are delivered immediately upon the conclusion of each hand. Done deal.