These men are beating each other senseless using fluorescent tube light bulbs as weapons. This is apparently a sport in Japan. I can't find much information about it online, so I take it that it is not a widely popular sport. One blogger said "It's like WWF meets WTF." -- which seems like a good summation. There are more pictures at the link. Content warning: graphic violence.

Link via Geekologie | Image: Blue Circlet