What is a good, practical 50th anniversary gift for friends (not family)?

Friends of our family are having a 50th anniversary party tomorrow. They are simple people, they have a house but it is plainly decorated, without a lot of crap in it. They don’t use computers. They are both in their 70’s. They have a large family who is throwing the party, and since it’s last minute, I am not able to do something crafty as a gift.

What is a good practical gift I can give them? The party is tomorrow (and of course I forgot about a gift until now) and any and all suggestions are appreciated.