Install pay-by-the-hour lockers on station mezzanines so that riders can secure their personal items, like they might do with the trunk of a car.
Many times, I've wanted to take a quick trip somewhere after work, but chose not to because of the hassle of my laptop bag. If I'm going for a run at Banneker (near Shaw-Howard), I'm too worried to leave my bag out in public, and I also can't run with it. If I drive there, I can just leave it in the trunk without much worry. If I could keep my bag in a locker at the station, I might choose to get there via Metro. This also applies to bars during after-work happy hours, etc. This wouldn't be appropriate for every station, but for key downtown stations it would be a great amenity and potential revenue generator for Metro.