I recently assisted at a wedding in rural VA where the theme was simple outdoor bbq. It was casual, easy-going and tons of fun. Although not everyone is in for their wedding be casual, there were still some great ideas that anyone could use.
Ceremony: The couple had the ceremony in the backyard and used blankets and pillows for people to sit on instead of chairs. This is a great idea if you are having your wedding outside somewhere where you would have to rent chairs to be brought it. It escalates the bbq feel and can still incorpoarte all your wedding colors.
Centerpieces: the centerpieces were old glass bottles of all shapes and sizes arranged with white votives. Once it got a little darker outside, the flame and glass gave off amazing light and texture.
Decorations: I am persoanlly in love with this cheap, amazing way to let people know what is going on. Again, this may not work if you are not having an outdoor wedding/reception. Save money on printing menus and programs and use chalk boards to list what is going on/what is being served. You can find chalkboards in all shapes and sizes and can paint the rim to match your wedding colors. Then find someone with nice handwriting to write your message. Chalkbaords can easily be hung from trees with cord/ribbon, leaned up againist anything and still look professional.
Food: Although they did hamburgers and hotdogs, which we cooked, you can still incorporate your favorite bbg food into a catered meal. Put a spin on potato salad or roasted corn. Add more sophoisticated ingredients to make a simple dish more elegant.
Dessert: Everyone's new obsession is cupcakes, which the couple pulled off. Since the wedding was so easy-going there was no cake-cutting ceremony, guests could grab cupcakes as they pleased. I think cupcakes are a great addition to a wedding. If you are trying to save some money, purchase a smaller wedding cake and then bake your own cupakes for the guests to eat, or purchase them if you are not kitchen savvy.
Games: This may not work unless you are outside, but the couple added fun bbg games for people to play. They had corn-hole, horseshoes, dice and card games, and quaters for people to play while drinking and enjoying the night.
A summers evening wedding can be perfect for a smaller wedding or for anyone who cares less about being flashy, but cares more about having a fun, simple night. All these ideas can be incporporated to fit different themes and still have a huge impact.