'Curveball' was a pair of Allied exercises ('Curveball I' and 'Curveball II') for airborne elements in preparation for 'Overlord' (27 April and 6 May 1944).
Basic overview
Start date: 27 April 1944 End date: 6 May 1944
Scope: Minor
Nature: Airborne, Training/development
Status: Implemented