The opening scene to Saving Private Ryan. Don't know if its the same scene or later in the movie a young solider is dying and calling out for his mother. Its pretty terrible.
And Toy Story 3. Seeing Andy grow up and pass along his toys and childhood memories to a new generation of children, the inevitability of growing up, the loss of innocence. I was sitting on the couch on a Saturday afternoon trying to be a normal person, watching a movie about toys come to life and whatever mischief they get into. Next thing I know I'm crying thinking to myself "The toys...they just want to be played with! That's all they know!"