The name of this film alone is enough to make me laugh. Tongan Ninja tells the story of a Tongan ninja who travels to New Zealand to help a Chinese restaurant defend itself against greedy gangsters. It's a Z-grade kung fu parody made by a bunch of Kiwis with some digital video cameras, and the plot is lifted directly from the Bruce Lee film The Way of the Dragon. Tongan Ninja is probably most famous now (if at all) for featuring an early appearance from Jemaine Clement (Flight of the Conchords) as the bad guy, but it's also one of those films that are so (intentionally) bad and over the top that it's hilarious.
Kung Fu films are very easy to parody but there's something about setting this film in Auckland, New Zealand, that just cracks me up. It's got no budget, is literally so bad it's good, features a stackload of deliberately lame lines that make fun of the genre, has cartoonish characters and plot, and makes use of some truly shocking CGI. It's very silly, but also very spot on. As it's shot on a camcorder this means that the characters are overdubbed, but this actually fits with the kung fu parodying and so the bad overdubbing works to the film's advantage.
Some things I loved: