This is how you dress up as Horton from Horton Hears a Who for Dr Seuss Day at work.
Step 1: Make a pattern. Cut two ears from gray felt.
Step 2: Use the pattern to cut out batting then trim to make the inserts smaller than the felt.
Step 3: Set up the sewing machine.
Step 4: Straight-stitch approximately 1/4 inch from the edge of the felt with the batting sandwiched between (but don't stitch across the channels you made for the headband).
Step 5: Show one of the cats the partially finished ears. He is unimpressed because you won't let him eat thread.
Step 6: Trim any excess batting then zig-zag stitch around the edges of the ears (again, not stitching across the headband channels).
Step 7: Cut apart a stretchy Goody sports headband, thread through the channels in the ears, and re-sew the ends of the headband together.
Step 8: Try and get one of the cats to model the ears. It doesn't work so well.
Step 9: Take a picture of yourself at work. With luck, one customer will get right off the bat you are Horton. The others will stare at you then ask if you're a moose.