Yesterday, a DJ mused on-air about how she enjoys soundchecks at concerts. I second that. It's fun to hear artists give the audience a hint of what they'll hear during the concert while sounding off-the-cuff about it.
During one soundcheck, I saw Erin Bode sing an excerpt from Bob Dylan's "Ring Them Bells" and then say, "I'll take a little more in the monitor." At another soundcheck, I saw Ralph Butler gently chide a band member by saying good-naturedly, "You call that a drum solo?"
Obviously, soundchecks are a necessary way to make sure the sound levels are set properly before a concert starts. However, they're also a fun glimpse into the performers' personalities.