Here’s a nerdy tip for Mac users. Open Automator, and create a new Service workflow. Set it to receive no input, then drag a “Run Shell Script” item into the workflow. Replace the default “cat” in the text area with this:
echo -n `uuidgen | tr A-Z a-z` | pbcopy
Save the service as “Copy New UUID to Pasteboard”. Now whenever you run the service, it generates a fresh UUID that is on your pasteboard, which you can then copy into whatever context you need it.
If you never need a UUID, then, umm, maybe just don’t worry about this tip.