If you're looking for some synonyms for "just for fun," you may find ample options that can add some flair to your vocabulary. You could use "for kicks," which implies doing something for the excitement or pleasure of it. "As a lark" is another great option as it highlights the playful or mischievous nature of an activity. "For amusement" or "as a pastime" are more straightforward options that emphasize the pleasure-seeking aspect. "In jest" or "for a laugh" show that the activity is meant to be silly or humorous. No matter which synonym you choose, remember that the underlying idea is to do something for enjoyment or entertainment, without any serious intentions or consequences.