9.  Arrays. subscripting, arrays + methods (?), pre-defined array 
    operations, area cloning, equality, vectors, sorting, searching,
    procedssing command-line arguments. Multidimentional arrays: opps,
    defining ops, matrix class

vectors not (yet) supported. (No garbage collection yet, although
that is coming).

*) Extend button class to store an array of listeners.
   
*) store an array of directions which were taken, and then do the
   reverse to get back to the starting (roughly speeking, perhaps
   use the rotation sensor in conjunction).

*) Samplings from the temp sensor to see how fast it changes in 
   a specific setting (in air, in water). 
  
*) Wumpus world (AI ... probably too hard)

*) Map builder. (Also, i'd imagine this would be too hard)

*) Array to keep sound note information, make a class 
   to play them (w/ sleep where approriate).

*) Array for direction instructions (both motor directs, motor power).