What do they do at dog trials?

A dog trial is supposed to "test" your dog's ability to function as it was bred to do, but seeing as most canines are used as companions rather than workers these days, that kind of thing is becoming obsolete. I don't really find it necessary to go to one of these, but it might be a good idea to go to one anyway. You never know if it might teach you a thing or two about the care and needs of your dog, or pick up people's opinions on how you're keeping up your pet. Example: "Boy, that dog is so fat! What'cha been feeding it, 'cause I think you eatin' the same thing!"