Scroll down on the page under number 1, the first section.
There is a DARK RED bar you can click. Click it.
It opens up a new window and gives you a 48hr Code & another random Jap code.
I do not know what this other Jap code is, I cannot get it to work on Xbox.com or on my dashboard. I think it is an ingame code for MonsterHunters.

If anyone figures out what this other code is for please post and let me know. Thanks!
http://xbox360.mh-frontier.jp/contents/48h_play/?uid=116629536&tid=11624

I came across this on my Japan account, in my email.