Something my students enjoy is collecting data over a period of a week, or month and then graphing the information.  We do weather in second grade and record how many days in the month were sunny, cloudy, rainy, etc.  In third grade you could do the temperature  and  create graphs for each month of the school year.  At the end of the year, close to EOG time you could use your graphs to discuss temperature, median, mode, range, and even misleading graphs.  Always try and link graphs with other concepts and curriculum areas so that you are integrating and make it relevant.  Using food is always great, try M&M's or at Valentine's you can use the sweetheart candies!