I actually got to spend a little bit of time researching things for this lesson. My oldest child enjoyed learning about the differences between true wheat and its look-alike counterpart: tares. The fascination that they truly couldn't be told apart much until harvest time when the lack of substance in the heads of the tares made it apparent as a counterfeit, and the intrigue of the trivia that eating the seeds of the tares would make one sick made this lesson stick before we even made it to Sunday morning.
I covered the lesson by again asking for someone to read, and we talked about who the enemy might be, as well as what the whole story was. Then, we read the explanation of the parable to "check" ourselves.
I had found a YouTube video made by a class of elementary Sunday schoolers that did a great job telling the parable, so we viewed it together, and I think that helped with their overall comprehension. You can view it here. Because it was made by their peers, it was highly interesting. Because it was multi-media, it was highly interesting. And it really was very well done.
During the activities time, I used this colouring page from the online King James Bible with is part text, part pictorial. Because it requires thoughtfulness, we read it together before colouring I appreciate it because it helps even non-readers be involved, but it is detailed enough to be interesting for older children. We also coloured this from BibleWise.com and had this word search from LivingWatersBibleGames.com and a maze available. It's fun to see how each child chooses activities and how some of the older ones help the younger.