serendipity

noun. finding good things without looking for them, unexpected good luck

The word was coined from a fairy tale, in which, three princes made all types of wondrous and delightful discoveries about an island, and learned things they never expected. The island called Serendip is known as "Sri Lanka" today.

"You can thank serendipity if you find a pencil at an empty desk just as you walk into an exam and realize that you forgot yours."
"make use of serendipity to find future collaborations"
"serendipity comes to the people who are prepared"

http://whatis.techtarget.com/definition/serendipity