The Ask homepage has recognized Memorial Day with an image and link to customized search results. While Memorial Day is specifically an American holiday, Thanksgiving is also specifically American and most search engines had fun with their logo on that day last year. Yahoo!, Google and Microsoft apparently skipped the day for custom search, while Ask has nicely provided references to the history of Memorial Day, recipes and other observance tips.
Postscript: We can expect most holidays to be highlighted on Ask in the future. Our friend Gary Price wrote in to explain the Memorial Day reference at Ask is part of their Smart Answers feature which automatically includes Holidays such as Labor Day, Boxing Day, Good Friday and Purim. Smart Answers really seems like a throwback to the past with Ask(Jeeves) having started life as a directory of answers to approximately 200,000 questions. They originally provided editor qualified sites as "answers" and backfilled as a meta search engine to supplement and in the cases queries didn't trigger a response from the directory itself.
Postscript 2: To clarify, Smart Answers are different insofar as one doesn't need to pose a question. They also can provide access to more information, including Smart Answers with drop down menus to more Smart Answers. A query like dogs provides a drop down menu that navigates to more Smart Answers on specific breeds.