I finally went to my first Yomiuri Giants game (and thus my first game in Tokyo Dome) 10 days ago. I'll have a few pictures from the stadium eventually (probably posted to my other blog) but I should note that I received a free card when I walked in the gate:
The card was tossed in the bag handed out at the front that is full of advertisements. It really pays to take everything being handed out as you enter a game - I got that and a player guide in the bag, plus they were handing out Pikachu/Giants cardboard hat things and tickets where you could win a prize. The odds aren't terribly bad - about 2% of tickets were winners of some prize.
As I mentioned, I'll talk more about the stadium and my game experience in a full post later, but I wanted to share this card (which is very welcome in my type collection!) with you.