Our final project of the year in my intermediate classes was painting 16x20 canvases with beautiful landscapes.  The students chose their own reference photograph and synthesized much of what they had learned through the year to create the paintings, and they were lovely!  They spent 5-6 hours on these.  

The newest editions to my art room are black-out shades, blacklights, and fluorescent paints!  This allowed us to have an awesome end of the year party, at which we painted ourselves, our papers, our plaster hands, the tables, and even the poor floor, which kids said looked like a galaxy (it came off easily!)  

Why a glow party?  I want kids to remember their unique art experiences when they're 80 years old with a great-grandkid on their lap.  I want them to say, "I remember when I did ________ in my art class."  I think this is one memory that will stick!