5 Google Apps you may not be aware of.

1.  Google Building Maker.  http://sketchup.google.com/3dwh/buildingmaker.html This is a part of Google Earth that allows users to build 3-d renderings of buildings within the map.  Users can volunteer to construct any building utilizing tools provided by Google.  The creator can then submit the building to Google’s 3D Warehouse where it will be reviewed and possibly accepted.  Accepted buildings will give credit to the creator.  If you see a building that has been previously created, but think you can do better, you are welcome to submit your creation as well.   Cities currently enabled for the new Building Maker include:  Austin, Dallas, Atlanta, Denver, Philadelphia, Chicago, San Francisco, Athens, Venice, Barcelona, Tokyo, and Dublin among several others.
2. 2.  Google Squared . http://www.google.com/squared  Google is a highly regarded search engine utilized by millions of people every day.  If you’ve ever used any search engine, then you know the haphazard results you may receive.  This is where Google comes in.  Google Squared returns search results in a spreadsheet-like format and creates structured results based on your query.  Placing structure on the otherwise chaotic and unstructured data typical of search results can make the results far more usable.  For instance, doing a search on LCD TVs results in a very useful grid of comparable data that can be used in the evaluation of purchasing a new television.
3. Google Translate.  http://www.translate.google.com/  Google offering translation services can be very useful for the internationalization of knowledge.  How many times have you been searching and realize that the information you need is in some foreign language, but not sure what language it was?  Google Translate has a Detect Language feature that will identify the language and then translate it into English (which is the default). 
4. Google Listen.  http://listen.googlelabs.com/ First off, this app is for Android users only.  Having said that, Google’s Listen is a search engine for audio.  Listen can be a podcatcher to manage and listen to your podcasts or just a search engine for audio.  For example, if you search for a topic like Cameras, the result will return podcasts and other web audio related to that term.  A great tool for podcast enthusiasts or for anyone looking for audio clips.  If only this was not limited to Android systems.
5. Google Latitude.  http://www.google.com/latitude/ Latitude is a feature of Google Maps that tie into your mobile devices and shows your location and the location of your friends on the same map.  Wondering where your buddy Ned is?  Check the map and see he’s just 2 blocks away.  Location is approximate, but approximate is typically good enough to know that your wife is at the mall.  Latitude also allows you to communicate with those friends on the map via SMS, Gmail, Google Talk, or simply with a status update.   Worried that people are tracking you without your knowledge?  Fear not, the system requires you to specifically opt-in for people to see you and your location, plus you can log off at any time which will disable the tracking.