Any suggestions for a 25th wedding anniversary?

I need some suggestions, that are low cost, to celebrate my upcoming 25th anniversary. We have a son in college, a small business, and want to make it special without going to great expense. I have dinner planned. But, I need little things to add to it, to make it special.
In this day and age, 25 years and still in love, is major. This is not something I want to blend into everyday.
I have a little over a month to plan the rest of this night. Any suggestions?