Classic movies begin with a story and if that's what you're looking for, there are some great sources available to you.  For example, you can visit Netflix and within each movie genre you can get story ideas by just passing your mouse over the movie thumbnails.  Also check out: Plot-O-Matic, Movie Plots, The Movie Spoiler, and The Internet Movie Database.  In fact, just Google "movie plots" for lots of good ideas. Norman Hollyn has written a great book on storytelling titled The Lean Forward Moment, about story structure, that is well worth the read. 

When you have your story there are some great script writing programs available, such as Final DraftStoryist, and (for free) Celtx. Some of these programs include a storyboarding feature as well.  If you would like to hire a writer and do it up right, try,, or The Scriptwriters Network.  

However, back to reality, most home movies are not professional productions. With a limited budget, it can be challenging to serve as writer, director, actor and  cinematographer, all in the same scene!  When you are appearing in a scene yourself you can hand your video camera over to complete strangers, but depending upon where you are, that has been known to spell the end of a production.  If you want professional talent on the filming end, try Googling "videographers."  Choosing a local videographer to shoot a few scenes can be a great help.  If you decide to do it yourself, there are lots of informative "how to" movies right here on Cineplots.

Although editing is sometimes called "the invisible art",  for me it is the essence of story telling.  High costs made this art practically inaccessable to the amateur just a few years ago.  Today, with programs like iMovie, Final Cut Pro, and Adobe Premier editing tools are available at an affordable price. And, if you don't feel like getting involved in editing, you can always let a professional do it for you.

"Retroscripting", or scripting on the fly, is an easy way to add a plot to your home movie.  You can find a basic plot using one of the aforementioned techniques.  With the plot in mind, film some ad-libbed scenes, then sew it all together during editing.  Plots involving being chased by someone, trying to find someone who has been abducted, body replacement by aliens, etc. lend themselves to this approach.  The result can be interesting and it is a lot less work than fully scripting your work.