This is intended to reify the best practices found here into a concrete example.
# staging (whole site)
ansible-playbook site.yml -i staging
# staging (just databases)
ansible-playbook database.yml -i staging
# staging (just job servers)
ansible-playbook jobs.yml -i staging
# experimental (whole site)
ansible-playbook site.yml -i experimental
# experimental (just databases)
ansible-playbook database.yml -i experimental
# experimental (just webservers)
ansible-playbook webserver.yml -i experimental
# production (whole site)
ansible-playbook site.yml -i production
# production (just webservers)
ansible-playbook webserver.yml -i production
# production (just job servers)
ansible-playbook jobs.yml -i production