Something I do with my kids every night after bedtime stories: we each think back over the day and tell each other what the best part of our day was. I started doing that in a bid to get them in the habit of noticing good things through the day and it seems to be working. Also, they love it - more than stories or songs. We can miss stories and songs some nights if we're out late, but they won't go to bed until we talk about our day.