Evening Bags and Fun Casual Bags. Selecting the right bag for a dressy event is, in many cases, an art form. Formal dress codes, like weddings or black tie occasions, require a unique bag that often isn’t already in your closet. It has to hit the crucial mix of matching your dress while still standing out on its own. It can’t be too big where it looks like you’ve brought along a laptop as your plus one, but it also needs to be capable of carrying the essentials: phone, wallet, keys, lipstick.