The goal in this competition is to take an image of a handwritten single digit, and determine what that digit is.
The data for this competition were taken from the MNIST dataset. The MNIST ("Modified National Institute of Standards and Technology") dataset is a classic within the Machine Learning community that has been extensively studied. More detail about the dataset, including Machine Learning algorithms that have been tried on it and their levels of success, can be found at http://yann.lecun.com/exdb/mnist/index.html.
Here is a basic implementation of Random Forest on the competition data.
Here is an implementation of K Nearest Neighbors on the competition data.