A quick Secret Santa generator. You can specify restrictions (e.g., don't let Larry draw Jen's name). Set the three TODO sections (line 14, line 17, and line 74) before running the script.

santa.py

#! /usr/bin/env python

# Usage
# ===============================
# test run
# ./santa.py --test
#
# game time
# ./santa.py --password EMAIL
#

import argparse
import datetime
import random
import smtplib
import string
import sys

# set this with the --password switch at the command line
OUTBOUND_EMAIL_PASSWORD = ""

# TODO: configure these for your environment
FROM_ADDRESS = 'santa@'
FROM_ADDRESS_NAME = 'Santa'

# TODO: set your exchange participants and any restrictions
ppl = {
  # people in draw: [ 'cant', 'get' ]
  # e.g.,
  # mark: { 'email': 'mark@some.org', 'dont_match_with': [ 'mark's wife', 'whomever mark had for the last exchange' ] },
  'p1': { 'email': 'p1@some.org', 'dont_match_with': [ 'p2', 'p3' ] },
  'p2': { 'email': 'p2@some.org', 'dont_match_with': [ 'p1', 'p3' ] },
  'p3': { 'email': 'p3@some.org', 'dont_match_with': [ 'p4' ] },
  'p4': { 'email': 'p4@some.org', 'dont_match_with': [ ] },
  'p5': { 'email': 'p5@some.org', 'dont_match_with': [ ] },
}

# Global functions
def create_argument_parser(script_description, arguments):
		"""
		Configure an ArgumentParser object to handle command line options
		and arguments

		Arguments:
		==========
		script_description (str)
				The friendly description of the script

		arguments (dict)
				A dict setup as { 'arg': { 'help': '', 'required': '', } } 
				describing the accepted arguments

		Output:
		========
		(argparse.ArgumentParser) Fully configured parser for command line
															arguments
		"""
		parser = argparse.ArgumentParser(description=script_description)

		for arg, vals in arguments.items():
				parser.add_argument('--%s' % arg, 
														action='store' if not vals.has_key('action') else vals['action'],
														required=False if not vals.has_key('required') else vals['required'],
														default=None if not vals.has_key('default') else vals['default'],
														help=vals['help'] if vals.has_key('help') else '',
														)

		return parser

def send_msg(to_name, to_email_address, match_name):
	# Cribbed from http://segfault.in/2010/12/sending-gmail-from-python/
	session = smtplib.SMTP('smtp.gmail.com', 587)
	session.ehlo()
	session.starttls()
	session.ehlo
	session.login(FROM_ADDRESS, OUTBOUND_EMAIL_PASSWORD)
	headers = ["from: " + FROM_ADDRESS,
           "subject: " + '*** Secret Santa pick for %s ***' & datetime.datetime.now().strftime('%Y'),
           "to: " + to_email_address,
           "mime-version: 1.0",
           "content-type: text/html"]
	headers = "\r\n".join(headers)

	# TODO: customize this message for your gift exchange
	body = ("""
	<p>
	Merry Christmas %s!
	</p>
	<p>
	Your pick for this year's Secret Santa is <b>%s</b>.
	</p>
	<p>
	As with other years, the kids from the Secret Santa exchange.
	</p>
	<p>
	This year the limit is $___--not including shipping. Remember if you're sending something across the country, the last day for shipping is ___.
	</p>
	<p>
	Happy holidays,
	<br />
	   Santa
	</p>
	""" % (to_name.capitalize(), match.capitalize())).replace('\t', '')

	session.sendmail('%s <%s>' % (FROM_ADDRESS_NAME, FROM_ADDRESS), '%s' % to, headers + "\r\n\r\n" + body)

def generate_matches():
	matches = {}
	remaining = ppl.keys()

	for p, data in ppl.items():
		match = random.choice(remaining)
		matched = True
		if match == p: matched = False
		if match in data['dont_match_with']: matched = False

		if matched:
			matches[p] = match
			for i, r in enumerate(remaining):
				if r == match: del(remaining[i])

	return matches if len(matches) == len(ppl.keys()) else None

def get_valid_run(test_only=False):
	# trying to solve this elegantly is actually a waste of time
	# it's much simpler and faster to re-run the matches if we
	# don't have a valid set (e.g., p1 is matched with someone they 
	# shouldn't be)
	num_of_matches = 0
	total_run = 100000
	final_selection = None
	for i in range(total_run):
		matches = generate_matches()
		if matches:
			num_of_matches += 1
			final_selection = matches
			
	# let the user know how many runs we went through
	print '%s %% (%s/%s)' % (num_of_matches / (total_run * 1.0) * 100, num_of_matches, total_run)

	# create an anonymous mask to display the results
	anon = {}
	for i, k in enumerate(ppl.keys()):
		anon[k] = string.letters[i]

	# print out a final select key (it's anonymous)
	for k, v in final_selection.items():
		print '%s\t%s' % (anon[k], anon[v])
		if not test_only:
			send_msg(k, ppl[k]['email'], v)

if __name__ == "__main__":
	arg_parser = create_argument_parser("Simple Secret Santa generator", {
		'password': { 'help': 'The password for the outbound email account' },
		'test': { 'help': 'Create a test run for the generator. This will NOT send out emails', 'action': 'store_true' },
	})
	args, potential_ips = arg_parser.parse_known_args()
	args = vars(args)	

	if args['password'] and len(args['password']) > 0:
		# set the password for the email account
		OUTBOUND_EMAIL_PASSWORD = args['password']

	if args['test']:
		print "*** TEST RUN ***"
		get_valid_run(test_only=True)
	else:
		get_valid_run()

# test run
./santa.py --test

# game time
./santa.py --password EMAIL

FYI, this is queued up to use a Gmail account. Change line 72 if you want to use another provider

some errors:
Line 105: to should read to_email_address
Line 103: match.capitalize() should read match_name.capitalize()