U2 sold out its August 25 concert at Slane Castle in County Meath (outside Dublin, Ireland) so quickly (45 minutes) that they wanted to roll over a second concert due to the numerous fans still waiting on line for tickets.
However, U2's promoter was not permitted to sell tickets for a second show at that time. Under current Irish laws, the promoters failed to secure planning permission, and did not apply for, and have time allowed for objectors to state their case. The government is going to try to change the laws for the future, and it is felt that U2 will soon be able to add a second show at the outdoor site.