The Angels are grounded due to a safety stand down. They performed a manouver too low and are now grounded for training and review.
http://www.blueangels.navy.mil/media/news/20110526_001.pdf
This is the first time in 4 years they were supposed to come to KMIV, and I’ve never seen them before. I was supposed to go with the Civil Air Patrol and camp out overnight between the shows next to their hanger…ugh. 
But it must be serious if they had to scrub the USNA’s graduation as well.