I was at this show. I ended up getting tickets earlier in the week, and here's how the show went down...
Pearl Jam came on around 8:20, played for 30-40 minutes (you could see lightning off in the distance while they played, which looked really cool) when Vedder said that they had to stop to allow the storm to pass and everyone had to evacuate the field. He said it would take about a half hour to evacuate and the storm would last a half hour. He also said that the curfew would be extended. So, they were probably expecting to go back on around 10 pm. Shortly after, it was raining really bad. I was in a covered section, but after a while, the rain started permeating through the roof, getting everyone wet. My girlfriend and I were attempting walking around Wrigley for a while. It was so crowded, some people were fighting, someone actually fell and got hurt in the 200 section. I was expecting them to cancel as it got later. Then around 11:30, they uncovered the instruments on stage, which sent the crowd into a cheering frenzy. Then they let people back on the field (I thought about trying to sneak into the general admission section, but wussed out), and Pearl Jam came back on at almost midnight. They played a great set and went until a little bit after 2. Eddie said they would like to do this every year...
But besides the delay, it was a great show. The crowd was really into (as they are at every PJ show). It was great to hear Present Tense and Crown of Thorns. I was gonna go to Megadeth in Milwaukee that night, but after seeing that setlist, I'm much happier to have seen Pearl Jam.
4/23 - The Knife
4/26 - Possessed
5/7 - QOTSA
5/16 - Slayer
6/15 - Eyehategod