An interlude is a brief period of time that comes in the middle of something. You might enjoy a relaxing lemonade interlude in the middle of a tough day at your road-paving job.
Any block of time that comes as a break or a respite from an activity can be called an interlude, so you could talk about a quiet interlude after a noisy birthday party, or an interlude of peace after years of war. Interlude is often used to describe the pauses between acts of a play or during an intermission. In fact, the original meaning came from the Latin interludium, which means "between a play".