First up, what is an oxymoron, you might wonder? The answer is that, essentially, an oxymoron is a pair of words combined that contradict each other. Examples can be humorous ('an organised committee') or genuine ('deafening silence').
Here, purely for your viewing pleasure, is a list of some oxymorons:
Synthetic natural fibre
End of infinity
A wise fool
Jumbo shrimp - Contrib. by Frances
Efficient civil service