"Oy vey" or sometimes just "oy"
"In all truths" though usually when I'm explaining something.
On a more nonsensical note "Woohoo! Good cheese!".
"So...yeah." which is something I picked up after watching so much Eddie Izzard stand up stuff over the years.
and recently, "Oh man, I LOVE it when 'X happens'...oh no wait. I don't."
Though I also tend to just quote movies and TV shows a lot of time as well so there's always that.