Like ICS, Honeycomb and Gingerbread before it, Android 4.1 Jelly Bean features a neat little "Easter egg" animation within the "About phone" and "About tablet" pages. On a Jelly Bean device like the Galaxy Nexus or Nexus 7, head to Settings > About phone and tap repeatedly on "Android version: 4.1" until you see the picture of the happy Jelly Bean guy filling the screen. Then long press on the middle of the screen, and you'll get a screen filled with more Jelly Beans, which you can fling around using your finger.
You'll also note the candy cane among the field of Jelly Beans. It doesn't always show up, but we've noticed it a couple of times already. We're not sure exactly why that's there, but it only seems to appear occasionally. (If you've got any wild theories, share 'em in the comments.)
Of course, all this stuff is still functionally useless, but it's a pretty cool visual treat regardless.