Scotch doubles, an enjoyable and social bowling format, pits teams of two bowlers against other teams. A team may consist of any combination of bowlers -- husband and wife, mother and daughter, father and son, two friends and so on. The Scotch doubles format, which is rarely used in official league and tournament play, requires the bowlers on each team to alternate throws or bowls.
You bowl and score three games to determine the winning team. Teams decide which player starts and bowls first. This player must bowl the first ball of each frame in the first and third game with her partner bowling first in game two. If any pins remain standing, the player's partner takes a turn and attempts to knock the pins down to score a spare. If the first or leadoff bowler scores a strike, she bowls again and her partner doesn't bowl in that frame. It's possible for the partner to never have a turn as long as the leadoff bowler rolls all strikes.
A variation to ensure each teammate has an equal number of bowls is to have partners alternate after each turn regardless of the outcome. If the first or leadoff bowler rolls a strike, her partner rolls the first ball in the next frame.