courtesy of www.groupon.com...
"...it’s illegal for gift certificates (including discounted gift certificates like those offered on groupon) to have expiration dates.
more info: http://www.dca.ca.gov/publications/legal_guides/s-11.shtml
1) most gift certificate will say “expires x/y/z unless in california”, but even if they don’t have the “unless in california” wording, the businesses aren’t allowed to enforce the expiration date.
2) if the gift certificate call the expiration dates “redemption dates” instead, the businesses have the option of giving you a refund instead of accepting the gift certificate."