Ideas for the gown and accessories.
There are plenty of alternatives more interesting than a tuxedo.
Matron of Honor/Bridesmaids
It's hard to beat a standard bridesmaid's dress for sheer terror, but here are some other options.
Suggestions for the male attendants.
Flower Girl/Ring Bearer
Ideas for the "flower ghoul" and her companion.
Depending upon who the person performing the ceremony is, they may want a costume as well.
If you want your guests to "get into the spirit," try these suggestions.