– The meaning of String[] args
– Maybe some kind of game or the Caesar cipher.
– Declaring, creating and using arrays
– Arrays can’t be mixed
– Multidimensional arrays
– Role-playing? Some sort of contest? 20 students in class. 4 groups of same or different lengths, with a script?
– Minesweeper! http://www.dickinson.edu/~braught/courses/cs132s03/labs/lab10.html
– Hangman
– Tictactoe
– Memory
– Die rolling and frequency statistics

Resources:
– http://www.javaforstudents.co.uk/arrays.html : basic, doesn’t show arrays as essential
– http://www.boutell.com/javaclass/ : cool