You could get the bride to give you or bring with her all of the pictures that she has of her & the fiance , and pictures of places they've been together while they've been dating and/or engaged, any pics of memorable places/moments/seasons,etc while they've been together. Go buy a really nice, very large leather-bound scrapbook album (that she could later have monogrammed or something inscribed on the front of it) and some nice, quality scrapbook supplies....make a "themed" scrapbook of their life together before marriage. I say to buy a large album because you could leave plenty of pages for her to add pictures of the wedding and pictures from their first year of marriage. And each "era" could be themed by color....dating/engagement - pink; wedding - silver/gray; 1st year - blue....or whatever colors you choose for the first part and she chooses for the other 2 later. Then all of you could help her do the pages of their "dating life" at the party.
ORRRRR.....if all of the bridesmaids have pictures of themselves with the bride, then all of you could bring whatever pics you have and do a scrapbook of her with her friends and then after the wedding you, another bridesmaid, or the bride herslef could add pictures of the bridesmaids and the wedding with all of you together at the end.
The only thing this requires would be an album, scrapbooking supplies and pictures! Quick, easy, fun and not too expensive unless you go over the top with the album purchase itself!