For preschool: put ABC's or have them match the labeled nuts (shapes, numbers, letters) to the bolt. Nuts and Bolts Spelling Practice: build fine motor skills and practice spelling/phonics skills! This would make a fun center activity.
Filth Wizardry: DIY spinny spellers and repurposing Duplo bricks. Several fun ideas for using Duplo and Lego bricks for language arts.
Letter toss game - working on balance, visual motor control and letter recognition; also great for visual scanning. Can use for almost any memorizing skill (alphabet, spelling, math facts, geography.