3. Jingles the Clown - Mr. Jingles (2006)
With a plot reminiscent of Halloween, Mr. Jingles follows the tale of Angie Randal, who is returning home on the 7th anniversary of the night she witnessed the slaughter of multiple families at the hands of Mr. Jingles, a clown seeking vengeance after being imprisoned for a crime he didn't commit. Mr. Jingles is one of the worst films on this list, but fans of gore and death will enjoy it. Gallons of blood and decent death scenes fill this film with sanguination (I just made that word up. It means "blood" or "gore"). Skip this one unless you're desperate for a clown slasher and all the rest are rented out already.
2. Happy Clown and Sad Clown - The Last Circus (2011)
This Spanish film is one of those rare movies (at least nowadays) that EVERYONE needs to watch. It is an instant classic. In 1937 Spain during the Spanish Civil War, the Happy Clown in a circus is forced into a militia. Still in costume, the Happy Clown is given a machete which he uses to slaughter an entire platoon of National soldiers. But the clown killings aren't done yet. We then flash forward to 1973 near the end of the Franco regime. The Happy Clown's son, Javier, wishes to follow in his father's circus footsteps. Unfortunately for Javier, he is a sad and emotionally damaged person who isn't remotely funny. In order to be a clown, he must play the role of the Sad Clown in the circus. Javier's life continues its downward slide as the Happy Clown in the circus constantly humiliates him. To further complicate matters, the Happy Clown continually beats the acrobat Natalia, whom Javier is falling in love with. When Javier is nearly beaten to death by the Happy Clown and spurned by Natalia, he takes a disfiguring revenge on the Happy Clown. Fleeing from his crime, the now completely unhinged Javier "adjusts" his appearance using acid and a clothing iron, giving him a permanent clown face. Then, as happens with all clowns, Javier grabs a couple of machine guns and goes on a murderous rampage against the Franco regime. The Last Circus is simply a great movie. If you haven't seen it, make sure you grab a copy.