Most people encountering the Ajax components of Django for the first time usually encounter this pairing:
from django.utils import simplejson
…
return HttpResponse(simplejson.dumps(some_python_obj))
For most applications, this is enough.  But I’m especially fond of iterators, generators, functors and closures, dense components that express one thought well: the structure of a tree, or the rows of a database, to be [...]