Thanks for the great question, JM.

There are plenty of stretching exercises you can use that don't involve yoga. This site lists nine of the most common stretches used by physical therapists - many of which I use myself. 

The important thing to remember is that a recent study, which was one of the largest of its kind ever conducted, found that people who use conventional stretching exercises and those who use yoga report virtually the same results. In other words, there's nothing special about yoga (except that it has its own line of exercise clothes). Those of us who are uncomfortable with the religious roots of yoga can forego it and get the same results elsewhere.