The warm, nubbly grain of the pigskin, the clean, sharp smell of autumn air, the sickening thud of an open-field tackle. Football season’s here again, thank God, a salvation for sports fans who can’t stomach the thought of watching Cal Ripken pop out to the second baseman again. Walter Mittys who believe that they could have made that last-second field goal or caught that touchdown pass can live their fantasies at NFL Kickoff ’93 on the Mall. Practice diving into the end zone, throwing passes at targets, and booting extra points. Then, when you’re convinced that you could make the Redskins’ roster, check out the exhibit where you compare your leg, bicep, hand, and foot sizes to those of NFL players. Today from 11 a.m. to 9 p.m. on the Mall at 4th & Independence Ave. SW. FREE. (202) 296-7200. (DP)