Today sees the launch of the 2013 edition of the Muscat Festival. This year, thankfully, it has been moved from Qurum park to Al Amerat Park and Sultan Qaboos sports stadium - along with long standing location, Al Naseem Park as well.
The two parks open every day from 4 -11pm, and the SQ sports stadium runs 4:30 - 11:30pm
The official website has a handy page showing you how to get to each of the three locations. The Muscat Festival has been running since 1998, and as far as I can tell has become incredibly popular. I've never actually gone to the Festival, and perhaps this year I'll brave the crowds and go and have a look!