I would wear something akin to "business casual", so pants other than blue jeans, and a cardigan over a top with a nice neckline. A cami would be great. Do you have any flats? In a pinch a very low-heeled pump would work.
For your DH khaki pants with a golf shirt (polo-collared shirt) would be perfect with some sort of leather shoe.
It's a cold weather climate up here though, so if you live in a warmer area, lighter clothes might be equally appropriate (in other words, no cardigan for you and a golf shirt with shorts for your DH).
Have fun!
" I object to violence because when it appears to do good, the good is only temporary; the evil it does is permanent." Mahatma Gandhi
"This is the ultimate weakness of violence: It multiplies evil and violence in the universe. It doesn't solve any problems." Martin Luther King, Jr.