I recently reenlisted in the US Navy and had to take the Oath of Enlistment again.  I was a Christian when I originally joined, but have since become an atheist.  There is a part of the Oath of Enlistment for the US Armed Forces that inlcudes "So help me God".  It is optional, but I failed to mention to the officer who administered the oath that I would be omitting that part.  Instead I had printed out a copy of the oath that did not have "so help me God".  When he started to administer the oath from memory, I knew he was most likely going to include that part.

Sure enough, when he got to the part he said "So help me God" and I didn't want to just stand there looking like an idiot, so without skipping a beat I repeated back to him "So help me Odin". 

It apparently caught him off guard because he hesitated for a second with a look on his face that said "did he just say Odin ?"

He almost started laughing, but held it back with a smile and continued the oath.  There were several people present, some high ranking, but mostly the guys I work with. Those who caught it were amused, including a Master Chief whose only comment was something very close to "That's right del Toro.  Don't let them push you around."