When does Hanukkah and Christmas fall again on the same year again?

They fall on the same year EVERY year. They just fall on different days of that year.

Christmas is always on December 25.

Hanukkah starts on the Hebrew calendar date of 25 Kislev, and lasts for eight days. Here are the coinciding secular dates for the upcoming years:

2011: December 20-28

2012: December 8-16

2013: November 27-December 5

2014: December 16-24

2015: December 6-14