What was the surprise encore piece performed by the LA Philharmonic on January 7th, 2011?

The concert was conducted by Dudamel... one of the LA Phil's Casual Friday performances. The last piece was by far my favorite, but it was a surprise, so it wasn't in the program, and I can't find the answer anywhere. If you happen to know, or know where to look (google's just not doing it for me) , PLEASE help!