A couple weeks ago I went to a sumo tournament--and forgot my camera. I had to make do with my phone camera, so the images aren't of as high a quality as I'd like, but anyway.
When we first got to the stadium where the tournament was being held, we hung out in front of the building for a while with the people waiting for the wrestlers to arrive. The matches actually started at eight in the morning, but the lowest-ranking guys wrestle first. I got there at around 2:00, and the "big-league" guys hadn't started yet. The final match with the yokozuna, the highest-ranking wrestler, ended the tournament at around 6:00.
Anyway, there were sumo wrestlers everywhere--even one on the bus with me. I just found something really funny about watching them get of little taxis and stuff.

Here's a picture of the sumo ring, taken from the ground floor hallway. As we were walking through the hallway, we passed more wrestlers getting ready for their match--there was no special section for them or anything dividing them from us, which was pretty cool.

Before the top division of wrestlers began their matches, they paraded out to the announcer-guy calling their names. There were a whole lot of ceremonial aspects to the tournament, which I thought was really neat.

And of course there were advertisements! What sporting event would be complete without a McDonalds ad? Not sumo! Apparently McDs was sponsoring the whole tournament or something, because when we walked in we were handed free McDonalds fans.

It was a really cool day, overall. The matches weren't like what I expected. There's no set "start" time for the wrestlers to slam into each other. They spend several minutes staring each other down in a sort of psychological warfare type thing, during which they can both start, or one can snub the other and walk off into the corner, for them to try again a minute later.
There's still a lot of rules and stuff I don't understand, but that didn't stop sumo from being really fun to watch.