How the heck do you use this with a portlet? (see answer below)

[dholth]

from zope.interface import implements, directlyProvides
from plone.portlets.interfaces import IPortletDataProvider
from zope.schema.interfaces import IContextSourceBinder

SomeVocabulary = NamedVocabulary("some.vocabulary")

def someVocabularyBinder(context):
    vocab = SomeVocabulary(context).items()
    return SimpleVocabulary.fromItems(vocab.items())
directlyProvides(someVocabularyBinder, IContextSourceBinder)

class IPortlet(IPortletDataProvider):
    value = schema.Choice(title=u'Some choice', 
        description=u'A choice', 
        source=someVocabularyBinder)

[tomgross]

@dholth What do you exactly want to achieve? Display a vocabulary as list in a portlet?