THE SIMPSONS annual "Treehouse of Horror" Halloween special. First, Homer kills off celebrities so their likenesses can be exploited free-of-charge in "How to Get Ahead in Dead-Vertising." Next, Transformer-like robots duke it out in Springfield in "Untitled Robot Parody." And in "It's the Grand Pumpkin, Milhouse," Lisa accompanies Milhouse to a pumpkin patch to await the appearance of the Grand Pumpkin, but when he finally appears, the Grand Pumpkin goes on a rampage to avenge all the pumpkins carved and tortured in the name of Halloween. Also, the highly-anticipated episode opener features Homer Simpson as he attempts to cast his ballot for the 2008 Presidential election with a deadly twist.