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Previously in Halo 2, if one were to change their date and clock on their console, one would find different signs for each date replacing the original "No Swimming signs" in Zanzibar. The same can be achieved in Halo 3, as Valhalla has different messages located on the Forerunner Wall. These notes will not appear if you are on split screen.

These can be accessed simply by changing the date on your Xbox 360.

• January 1st (New Year's Day): Make Love Not War
• April 22nd (Earth Day): A skull with a recycling sign.
• May 5th (Cinco De Mayo): Toady Was Live!
• July 4th: BBQ at Bob's Place (This is a reference to Marathon in which you kill BOBs or BOB-B-Qing)
• July 7th (Bungie Day): Seventh Column Symbol.
• October 31st (Halloween): A grave stone that says RIP(Rest In Peace).
• November 11th (Veteran's Day): Kilroy Was Here.
• December 25th (Christmas): A Christmas light with an X on it.

New Year Date Egg On Valhalla	Earth Day Date Egg On Valhalla	Cinco De Mayo Date Egg On Valhalla	July 4th Date Egg On Valhalla
Bungie Day Date Egg On Valhalla	Halloween Date Egg On Valhalla	Veteran's Day Date Egg On Valhalla	Christmas Date Egg On Valhalla