I have one for you:
Invoke a command that has a list of options, such as draworder. When done, hit enter to invoke it again. It will not show the items and will hang until you either select the screen or roll the mouse wheel or something. I've noticed this since the .NET was introduced. Often, and I know there's an issue with ACA2008 and draworder in general, but if I try to use the keyboard and the list wasn't up, it will crash autocad. As for hardware, etc. I've had this problem on multiple computers, so it's pretty persistent. Also, I have dynamic input enabled, but I'm sure that this is the problem.