Historical clue formulations

• Setter's activity — 2020-10-03
• Sport hinted at by the ends of 17-, 24-, 36- and 47-Across — 2019-01-29
• Piece of sports equipment that's spiked — 2016-05-16
• Sphere at the Olympics — 2006-11-14
• Picnic pastime #1 — 2001-07-09
• Game of digs and spikes — 1994-07-18