Before Pam nonstick spray, before WD-40, before halogen track lights, there was pure animal fat, a miraculous but now-maligned substance that was essential to life before spray cans. Today’s demonstration of The Many Uses of Fat on the Colonial Farm will revive fat’s role as lighting fuel, cooking substance, and lubricant, from 1-4:30 p.m. at the Claude Moore Colonial Farm at Turkey Run, 6310 Georgetown Pike, McLean. $2. (703) 442-7557. (Bill Gifford)