Any ideas? My parents will be celebrating 39th anniversary!? What can we do for them!? Details inside. ?

I am 25 and a total daddy's girl. I have two older sisters 35 & 30 and we are a very close family. My parents are celebrating their 39th ann. on March 1st this year. Any ideas. Nothing too big, because next years will be the "big one"! But a quick background is my parents are the most awesome ones ever!!! I am the youngest of three girls and there are 5 grandkids. Still all pretty young so they can't help with anything. Should we take them somewhere nice to eat? buy them a nice gift, send them somewhere, party? Put an ad in the paper? Any and all suggestions will be appreciated. Best answer tonight before I go to sleep!