Sponsoring a program, even on something unrelated to your field, helps get your name out to customers. It is free advertising for everyone who will attend the program. Also, your name and firm logo will be plastered on all of the materials provided to the attendees.
Plus, it is a nice way to give back to the community and stay involved with the businesses around you who will hopefully forward you some business (and hey, you can do the same to them)!