We have happening bars and couple kissas....
Happening Bars - Single Men, Women and Couples can enter... agreements can be made for swapping. (Example: Bliss Out) Entry Fee is lower for women, higher for men and a midrange admittance fee for couples. (if memory serves correctly)
Couple Kissa - Only couples are admitted. Swapping is done between couples. (Example: Olive21) Note: For Olive21, only men can be members. Entry fee is per couple.
You can search the site for more info about both of the example clubs.
Private parties happen too, but only by invitation.