California
Under California law, it is a crime punishable by fine and/or imprisonment to record a confidential conversation without the consent of all parties, or without a notification of the recording to the parties via an audible beep at specific intervals. The California Supreme Court has defined a confidential conversation as one in which the parties have a reasonable expectation that no one is listening in or eavesdropping. In addition to criminal penalties, illegal recording can also give rise to civil damages.
CA Penal Code § 632 (definition & penalty), § 637.2 (civil damages), Flanagan v. Flanagan, 41 P.3d 575 (Cal. 2002), Cal. Pub. Util. Code Gen. Order 107-B(II)(A)