M.M.
Yikes….not much time. What about trying to get some photos together from family and friends and make them a photo album. Something they could just browse through and reminisce? We did a DVD of photos for my parents 30th Anniversary with music in the background and it was a REALLY great gift. I am not that savvy when it comes to that, so we had to pay someone and it took a few weeks. But, you may be good at something like that.
Maybe get a copy of their wedding photo and have it blown up. Put it in a frame that all the guests can sign. Mount it on the wall after the part for them.