Happening or appearing now and then
Much of the show focused on Rachel's on-again off-again relationship with Ross, played by David Schwimmer.
George and drummer Moss were carrying on a volatile on-again/off-again relationship.
Lindsay Lohan and Paris Hilton have had a bumpy history, with an on-again/off-again friendship that has had some ugly verbal exchanges.
The on-again off-again teenage couple have shot down any rumors that their relationship is on the rocks and still plan on getting married sometime after the birth.
Salma Hayek married her on-again-off-again boyfriend Francois-Henri Pinault.