I have an Android desktop widget that shows me a random Chinese word when I look at my phone’s home screen. I really wanted this functionality on my laptop, so I wrote a simple Dashboard Widget that shows a random Hanzi word when I open the Dashboard. It’s called “Hanzi Challenge”, and you can grab it from my web site.
It shows you the word (in simplified or traditional characters; your preference) and displays the Pinyin pronunciation as a clue when you mouse over it. Click to see the English translation.