Do you have granddaughters? I would make some stuff for them, doll clothes, Barbie clothes, a play clutch for now, enough materials put away in a safe spot to make a clutch or something later (prom, marriage, babtisim or christening gown for a future great grandkids).
Do you have grandsons? Just put enough aside for a future daughter in law present or baby gift one day. Not many ideas for boys sorry. Maybe a pillow (so they always have you near them even if there away (camp, grandmas, ect.)
Just crafty? Take some of the pretty lace and put it on top of a pretty paper, drawing , whatever that matches your decor, find a cool frame.... Instant art! Or paint the lace put it over white paper, frame. if the lace isn't very tight knit, put some over paper spray paint and remove lace. I can't remember where I saw this (google lace pottery). This lady uses lace as part of her pottery, haven't looked it up myself but article said there are instructions online to do it. Do you put up nativity scenes or Christmas village up for the holidays? Hello snow! Cristmas tree skirt, fluffy bunny land, corpse bride.... The list can go on forever.
I wouldnt personally only use the material to make stuff that at some point will be old and ratty and need to be thrown out. Make sure you do one little thing that you can keep forever.
Good luck! Have fun!
BTW I saw it was a forty year old dress, I assumed it was your originally, so I talked of grandkids, if you younger and this was your moms dress, don't take offense to me referring to grandkids...I'm not calling you old! Again, good luck and have fun!