@Charles:OK, thanks. The ordering of the videos in the series' page is a little confusing what's even more confusing is that near the end of the video, when opening the solution for the challenge, the folder says "Challenge 5: Complex Event Processing"
This is the second video (after the introduction video) of the series, right? but I get the feeling that you're talking about things that I haven't seen in the first video (like when you said "if you did the last challenge you'll know where did that 'stock ticks' come from".) Maybe there's a problem with the ordering of the episodes.