Some sports books offer pre-made teaser and parlay cards that you can fill out prior to getting to the betting window. The most common type of these betting cards is the half-point parlay card. Each game is assigned a half-point spread (i.e. -3.5, -7.5, etc.) to prevent ties. Bettors can choose to wager on as many games as they'd like, usually up to 15 selections depending on the provider. The more games that you choose, the more you can potentially win. In addition to the half-point parlay cards, some oddsmakers offer pre-made teaser offerings as well.