Nintendo UK is having a bit of fun today in Animal Crossing: Let's Go to the City (known as Animal Crossing: City Folk in North America).
From the Nintendo UK site:
"Everyone likes a good prank - unless it's on you, of course. Life in Animal Crossing: Let's Go to the City for Wii reflects events in the real world, so don't be surprised if things get a little funny around town tomorrow (it's April Fools' Day, in case you'd forgotten).
If you don't mind being the butt of a joke, one local critter you'll definitely want to catch up with is Tortimer. Between 6 a.m. and 12 a.m., the old fellow will gladly enjoy a good chuckle at your expense. Who knows, maybe he'll even reward you for being such a good sport."