The "mass ascensions" are on weekend mornings. Check the schedule of events on the web site. balloonfiesta.com/event-info/event-schedule
I would say they launch every day (weather permitting), but mass ascensions are NOT every day, and that's probably what you most want to see. Years ago, they added another "mini" mass ascension on Wednesday morning and two special shapes ascensions on Thursday and Friday mornings. These are very popular for young and young at heart. The evening glows are not launches but are popular, too. Not every evening. The cross country gas balloons launch on the first Saturday. Most weekdays have competitions (a key grab, for example).
Mornings are the best for hot air balloon launches. Very early, and even on days when mass ascensions are not scheduled (and even before and after the official period of the fiesta) you will see many balloons in the sky over Albuquerque (even though not officially a mass ascension). These do not launch from the balloon fiesta grounds, however. More and more they are being launched on the west side but will float over the river valley and even up over the northeastern heights.
During the fall (on weekends other than the Balloon Fiesta), it's very possible to count over 30 balloons in the sky over Albuquerque just after dawn. The cool fall mornings (often windless) are conducive for hot air ballooning and I suspect several are commercial flights with visitors aboard.
We sometimes go to the new North Domingo Park in the very early morning hours on weekends. A new multi-generational center is in southeast corner (parking). There's also a skateboard park, a nice playground, a dog park, and they recently completed playing fields and a trail. (More to come.) That's not a bad place to view balloons from a distance. While I recommend viewing the Balloon Fiesta on the grounds for an experience unlike any other, several people are beginning to use this park and adjoining undeveloped fields for viewing balloons. When we are there on non-Balloon Fiesta mornings in the fall, it is almost certain we will count over 30 balloons in the far distance. It's also down the street from a Starbucks, so you can grab a cup of espresso and hot chocolate.
Edited: 11:37 am, May 23, 2013