Generate the basic plot of a story
Basic Plot Generator
Generates a new, interesting, and probably silly plot. I can't promise the plots will make any sense, so just keep generating if it's too crazy
By Story Genesis.
36 Dramatic situations
The Thirty-Six Dramatic Situations - Check out this list on Wikipedia of the 36 different dramatic situations largely gleaned from a book of the same name (full text here), about dramatic events that can occur in a story, including a short description and a few examples. Similarly, here is a link to a book called Ten Million Photoplay Plots that describes in more detail 37 basic plots. The book can be viewed toward the bottom of the page.