These are located outside the Eastern Market Metro though I’ve seen them at many metro stops across the city (Petworth had them for a while but no longer does). According to WMATA:
“Bicycle lockers provide excellent, secure bicycle parking by improving protection from theft, vandalism, and inclement weather. The lockers are designed to hold one bicycle each as well as bicycle gear such as panniers, locks, lights, etc. Users will receive one key that will only open one locker. Each locker has a unique lock and key to provide maximum security. Bicycle lockers are available for $200 for one year plus a $10 key deposit.”
Anyone have one? If so, did you have to go on a waiting list or were you able to get one right away? Does the $200 fee seem reasonable? You can see a list of stations with lockers here.