I copied this directly from the Give a Day Get a Disney day site. It was listed in the frequently asked questions part. I wasn't sure if I'd seen it mentioned that the two parks (DL and WDW) had different black out dates. Sorry if this is a repeat!
•The theme park tickets distributed under this Program will not be valid for use on the following dates:
◦For Walt Disney World® Resort: March 29 - April 8 and July 4, 2010
◦For the Disneyland® Resort: February 13-14, March 21, June 21-22, July 4, November 21, and December 11-12, 2010.
•The theme park tickets distributed under this Program will not be valid for use on the following dates:
◦For Walt Disney World® Resort: March 29 - April 8 and July 4, 2010
◦For the Disneyland® Resort: February 13-14, March 21, June 21-22, July 4, November 21, and December 11-12, 2010.
