Perfect timing, as I just finished a side-project I started a very long while ago. My topic was a practical training for a travel agency and my challenge was to make it as variable-based as possible. Here's the result:
http://bit.ly/270BeSZ While it looks quite simple, it uses 56 variables to track and calculate all aspects of booking, calculate the review score and populate the review comments. I went crazy with the variables as an experiment to reduce the amount of content that would need maintenance/updates. For example, the slide where you book accommodation is the same one for all three scenarios. So, if anything about the accommodation changes, you need to correct only one slide, instead of three. In the end, I cut down what could've been 33 slides to 11.
I'll try to add a blog post to explain the insides of the course in more details.
I made all of the images myself in PowerPoint - you can download them here:
http://bit.ly/1NfvIFl (free to use, attribution appreciated, but mentally thanking me is enough :) ). Note that if you preview the file from Google Drive it will display the London Eye as broken into pieces, but it's just Google Drive playing mind games with you.