Raijin is the Japanese god of thunder, thunderbolts, and lightning (as well as an annoying, stereotypical "dumb jock" who sticks the words "ya know" at the end of every sentence he speaks. Ya know.), traditionally depicted alongside Fujin (Japanese god of wind).
Like Fujin, Raijin closely resembles an oni (in appearance as well as temperament), with his crimson skin, tiger-skin loincloth (though most people nowadays think of someone more pleasant when you mention tiger-striped fashions), and menacing scowl.
Always shown in his unmistakable pose (reminescent, in some ways, of Bruce Lee`s Dragon kick), he rides on a cloud ringed by a series of drums set on a circular frame, upon which he beats out the rhythms of heavenly fury.
Unlike Fujin, however, some flimsy farm implements won`t trip him up; just try to stay out of open fields and you should be fine.
Sources:
http://www.kyohaku.go.jp/meihin/kaiga/kinsei/mht70j.htm (again, go here for a traditional illustration of
Fujin and
Raijin)
http://youmaya.hp.infoseek.co.jp/contents/bunko/huuraihtm.htm