Along with the collections library python also has a library called itertools which has really cool efficient solutions to problems. One is finding all combinations. This will tell us all the different ways the teams can play each other.

itertools_example.py

from itertools import combinations
 
teams = ["Packers", "49ers", "Ravens", "Patriots"]
for game in combinations(teams, 2):
    print game
 
# => ('Packers', '49ers')
# => ('Packers', 'Ravens')
# => ('Packers', 'Patriots')
# => ('49ers', 'Ravens')
# => ('49ers', 'Patriots')
# => ('Ravens', 'Patriots')