ss.py

import random

people = ['Aigars', 'Baiba', 'Centis', 'Daira', 'Edgars', 'Fins', 'Gita', 'Helmuts']
banned = (('Aigars', 'Daira'), ('Centis', 'Baiba'), ('Baiba', 'Centis'))

targets = list(people)
random.shuffle(targets)
pairs = zip(people, targets)  # zip( [A, B, C], [1, 2, 3] ) = [[A, 1], [B, 2], [C, 3]]

while( [1 for banned_pair in banned if banned_pair in pairs] or [1 for person in people if (person, person) in pairs] ):
    print "retrying"
    random.shuffle(targets)
    pairs = zip(people, targets)

print pairs