Eldarerathis summarized it very well. To add some things: The 1.1 version was internally called Petit Four by Google, and that's how it all began. Google is installing a giant pastry on their lawn at Mountain View each time a new version is about to be launched.

You can see pictures of that display at different stages here:

[Overall display (Cupcake to Ecliar, with Petit Four tribute)][1]

[Overall display (Cupcake to Eclair, with Nexus One)][2]

[Honeycomb][3]

[Eclair, Froyo, Gingerbread, Honeycomb and Ice Cream Sandwich][4]


  [1]: https://lh5.googleusercontent.com/-_fj468-OLGY/TFDnShiC5UI/AAAAAAAAeBk/navF07o8Rwk/s1024/697567251_img_7634.jpg
  [2]: http://farm5.static.flickr.com/4030/4453391412_8ec6dfa2a8_o.jpg
  [3]: https://picasaweb.google.com/104250970445890717876/Mobile#5579971667425251618
  [4]: http://www.androidguys.com/wp-content/uploads/2011/10/ice_cream_googleplex.jpg