Here's a fun little gem: "The rumor has it that Microsoft is uncertain whether to charge a license fee for a hyperthreaded processor as one or two CPUs." found in Wonderful World of Linux 2.6
I'm sure that many companies have had to deal with answering the question; "what is a CPU now?" What do you charge for software that supports 100 users on one platform and 1000 on another?
Let me know if you have an answer :)