Many bars have a discount period, designated a "happy hour" to encourage off-peak-time patronage. Bars that fill to capacity sometimes implement a cover charge or a minimum drink purchase requirement during their peak hours.
Bars may have bouncers to ensure patrons are of legal age, to eject drunk or belligerent patrons, and to collect cover charges. Such bars often feature entertainment, which may be a live band, vocalist, comedian, or disc jockey playing recorded music.