Have you ever gotten a song stuck in your head? I do all the time, mostly because I am tuned in to the music playing around me - whether it be in restaurants, bathrooms, waiting rooms, my house, the car, or wherever else. However since February Gregorian Chant has become a big part of my life. Melody lines as long as the the Tiber now swirl in my head as I go about my business. Sometimes all it takes is the drone of vacuum or a fan on a familiar starting pitch and off I go.
It might sound like a pennance to some people to have chant in their heads but its not. Its more like a perpetual meditation. For instance if all of a sudden the melody line for a Salve Regina comes into my head it makes me consider the words along with it. It ends up being a spontaneous prayer.
This is a benefit from the style of music. Since there is no accompaniment necessary, I carry all the tools to sing the entire piece. Often I end up humming the tune to the previous Sunday's Alleluia or Introit - effectively carrying the liturgy (in part) with me throughout the week. There have been times when I have left "ordinary" church services with bad music stuck in my head. But that doesn't turn into prayer, its just another headache.
Since Chant by its nature is "otherworldly" with melodies and text painting purposefully created to connect you with the meaning, it works to transport you to a higher level. If you aren't already, I recommend becoming familiar with some of the better known chant. Carry them with you.
There is a list floating aroud somewhere about 100 songs every Catholic should know. I'm going to try and find it...