Courir entre deux "O" is a late-November road race in Caen, Normandy. All races begin and end at Hélitas stadium. The event offers several distinct options: a 10 km race exclusively for women, a half marathon, and a 20 km relay for teams of two. Additionally, a 10 km walk is available for those preferring a less competitive pace.
The event's name references the Odon and Orne rivers, with race courses primarily situated within the city limits between these two bodies of water. The terrain is largely flat; the 20 km relay has only 29 meters of elevation gain, the 10 km has 36 meters, and the half marathon is noted as being essentially flat. It is presented as a communal, family-oriented occasion, not solely focused on elite performance, as individual runners, relay teams, walkers, and participants in the women's 10 km all utilize the same Caen stadium as a central point.