One of these pods was used by a time traveler to travel back in time to the 22nd century, where he had the misfortune of encountering Berlinghoff Rasmussen, an unsuccessful and unscrupulous inventor from New Jersey.
Stealing the time-pod, Rasmussen traveled forward in time to the year 2368, and made contact with the USS Enterprise NCC-1701-D. Passing himself off as an historian from the future, he attempted to appropriate various pieces of technology, including the android Lieutenant Commander Data, planning to return to his own time where he would pass the various technologies off as his own inventions.
Eventually, Rasmussen's plot was discovered, and he was taken into custody. As Rasmussen watched, the pre-programmed time-pod automatically returned to the 22nd century, stranding Rasmussen in the future. (TNG: "A Matter of Time")
Approximately five meters in length, the pod was constructed of a plasticized tritanium mesh, and its interior was accessed through a palm scanner on the outside. Used by time travelers, it produced a characteristic temporal distortion when traveling through time.
According to the script, this vessel was described as "a tiny multifaceted spacecraft" or "tiny ship".