I only sewed one thing for the baking party - aprons.
I made them in two sizes -
in heavy white twill, with a single pocket
little bits of trim
and top-stitching for color,
bias-tape bound armscyes,
and elasticized straps to slip over heads
and hang high on chests.
I left them plain white so the guests could personalize them with fabric pens during the party,
before they slipped them on and dove into some serious cookie decorating!
Note: These aprons were made the same way as in the old tutorial here.