for a lark

for a lark

On a whim or fancy; for fun or as a joke. For a lark, we all decided to ditch our Friday classes and drive to New York City for the weekend.
See also: lark

for a lark and on a lark

for a joke; as something done for fun. For a lark, I wore a clown's wig to school. On a lark, I skipped school and drove to the beach.
See also: and, lark, on