I spotted via a Google Groups forum thread posted by Pamela, a Google Maps engineer, that Google Maps had their own April Fools joke. I did not see this posted anywhere else, so I figured I make its own thread.
Pamela said she "put together a quick mashup to let you position a "trick" over someone's home." It is pretty cool, check out this link to create your own. Here are three samples over New York's Manhattan.
Why is it my favorite? Because this actually did happen on September 28, 2006. A bug got caught in the satellite lens and it appeared to spot an alien bug on Google Maps. Too funny Pamela!
Forum discussion at Google Groups.