The boy meets girl story is a basic, much-loved theme that fuels the story lines behind new romance novels and movies year after year. Put a fresh spin on the basic story, using your own personal experiences or those of family and friends, that you yourself find entertaining. Make a short movie about two people who would have never met, except for the occurrence of extreme circumstances, or a chance encounter that two people never forget about, until they somehow meet again, years later.
Animals are popular and well-loved characters in both live-action and animated movies, and adored by adults and children alike. Putting the family pet in different scenarios, such as a dog who hates water having to swim, creates cute and laughable results. Sometimes filming the pet going about its usual, daily activities, then rearranging the scenes with a bit of creative editing, will yield an enjoyable short movie. Animals dressed up in human clothes always get a laugh, but take it one step further and give the pet a job or task to accomplish in those clothes.
The whole world is one huge, new adventure for children. Everything to them is basically a fresh experiment and learning opportunity. Therefore, you have an endless amount of scenarios to place children in for viewing pleasure. A scrawny kid taking up martial arts, hating the dedication needed for it, but finally earning her first belt through perseverance, is cute. Keep in mind, especially if the children used in the movie are yours, to keep the children actually experiencing and "doing" something. Not everyone enjoys simply watching your children do nothing, like you might.
Sometimes comedy popping up within the mundaneness of everyday life itself is both funny and cute. Think of a comedian who puts a funny spin on an everyday event, like brushing your teeth, and makes you laugh. Create a short film that portrays a character trying to complete one simple, everyday task and encountering every inconceivable obstacle to getting it done. An example might be an overworked man trying to get to sleep before his next shift begins, but awakened each time he dozes off by everything from the phone, which he disconnects, to a barking dog to a wailing baby.