Polyamory is the practice, desire, or acceptance of having more than one intimate relationship at a time with the knowledge and consent of everyone involved. It is not to be confused with polysexuality, which is attraction towards multiple genders and/or sexes.

There is a group in Sacramento dedicated to giving polyamorous or poly-curious people a chance to meet each other and discuss polyamory: Sacramento Polyamory Meetup Group.

Polyamory-related events:

Some information from Wikipedia.