I have just found some VERY interesting news on nuketown zombies, as i have been looking on thetechgame for some clues towards playing nuketown zombies, and finding the easter eggs/ what to do in this map, and i came across nothing in TTG (although i did not look very hard) so i went and looked on the internet and found out the location of 3 teddy bears similar to the ones in Ascension, Teddy #1: Inside the bus in the middle of the map
Teddy #2: On the top bunk bed on the second floor of one house.
Teddy #3: In the backyard behind a fence of the other house. they all make a noise when you hold "x" on them and when all of them are found a song plays. and on round 5 you hear the bus leaving from nuketown going somewhere, my guess.. green run also on round 25 the zombies eyes change from yellow to blue, because Dr. Richtofen has become in control of the zombies, Heres the link to the info i found , i didnt say all of it here, i just wanted to say what i thought was important and see what you guys have to say , heres the link :http://ca.ign.com/wikis/call-of-duty-black-ops-2/Nuketown_Zombies_Easter_Eggs