Source : WordNet®

once in a while
     adv : now and then or here and there; "he was arrogant and
           occasionally callous"; "open areas are only
           occasionally interrupted by clumps of trees"; "they
           visit New York on occasion"; "now and again she would
           take her favorite book from the shelf and read to us";
           "as we drove along, the beautiful scenery now and then
           attracted his attention" [syn: {occasionally}, {on
           occasion}, {now and then}, {now and again}, {at times},
            {from time to time}]