So you must have seen the commercials for When In Rome, where the maid of honor is asked to smash a vase which is good luck. My first response to this was, "OK here is Hollywood making stuff up." But it is based on an old Italian tradition.
Here how it goes: In Southern regions of Italy, the couple shattered a vase or glass into many pieces at the end of the wedding day. The number of pieces represented the number of years they'd be happily married to one another.
Make it fun for everyone. Get small hammers and small (.99 store vases). Put the vases in cloth bags. Add a note about the tradition.
Just a note about breaking the vases, safety is key and you don't want pieces of glass, ceramics flying through the air and making a mess. DO NOT HAVE YOUR GUESTS SMASH THE VASES! Unless you plan on providing safety eye glasses too.