Just use the default parameter for a field:

import uuid

class ExampleModel(models.Model):
id = models.CharField(max_length=255, primary_key=True, default=uuid.uuid4)

Since I’ve been looking for this more than once:

import django
django.VERSION

I use Droid Sans Mono as my font for coding and in Putty and nearly everywhere. You can read and download it over at damieng.com.

If you want code and fixed-width text to appear nice in Firefox, what’s a better idea than using Droid Sans Mono there, too?

Go to Options > Content. Under Fonts & Colors click Advanced and choose Droid Sans Mono as monospaced font. It’s as easy as that. It will now affect every fixed-width text that is not formatted by CSS or something else. It will even change fonts in Firebug. I like it, it looks beautiful!