I wrote my own
I too wrote my own, basically a series of exercises of increasing difficulty focusing on core commands or techniques.
For example, I had one on co-ordinate entry that started by getting people used to the line command,
then progressed to arrays, then onto polar arrays getting people used to circles etc.
Then I had 'advanced' versions that took the same principles but made it a practical applications So for the coordinate entry/array exercise it was "Here's how to set out a regular building grid. Good, now add some circles to the gridlines. Good, now add the grid text. Excellent! Now copy the grid text across. Right, now lets put some dimensions on the grid. Right, on to the walls . . . ."
Pretty soon you've built up a fairly simple drawing with a real world example that has only used a few commands (line, circle, array, mtext, copy, rotate etc.) You can tailor it to suit the level of people you're working with "Right the 'architect' has changed his mind, we need to adjust the grid (stretch, trim, extend, erase, rotate) Hit all the basic commands and get people used to the selection processes, and they'll be drawing the basics in no time.