St. Mary's School (Medford, OR) is doing just that. Local public schools were forced to cut advanced music courses. So St. Mary's is filling the gap, offering before-school music classes. The local public high schools had an Honors Chamber Music Group with about 30 students in it. Those students now come, free of charge, to St. Mary's at 7:15 am and combine with St. Mary's chamber musicians. The students receive class credit at their respective public schools for taking the class at St. Mary's. The group is called the St. Mary's/Medford Honors Chamber Ensemble, with the St. Mary's music teacher, who is coming in early every day to teach the class.
In the evenings and on weekends, St. Mary's offers Mandarin classes to adults and students for a small fee, and will offer a French class in January. This helps St. Mary's fulfill its mission of preparing global citizens.
Auxiliary programs like this act as a community service and as a marketing tool for the school, but also generate revenue.
Does your division have courses or programs that could be adapted for public school outreach? It's food for thought. Of course, before implementing any program, your school needs to explore any risk/insurance ramifications and make sure offering the program will not have any unforeseen negative impact on the school.