Citysense is a program available for Blackberry devices (and soon to be the iPhone) which gives a visual representation of how busy the San Francisco night life is.
Citysense works by using Sense Networks Macrosense platform. The platform takes a ton of realtime location data (anonymously) and then displays this data on screen on a real time map. You will know exactly what spots are busy in town and at what time they get the busiest. This first version is just a test release (for San Francisco), but the final release will include even more personalised information about what kind of people are going out that are similar to you and where they are going. Citysense achieves this by tracking where everyone is right now and by comparing profiles it can highlight the areas where you would be most comfortable.
A number of people wont want to share personal detail, and if this is you then you can quickly remove your details from their servers with the push of a button. But, should you find yourself in an unfamiliar city then this software could prove valuable for a night out meeting new friends and similar friends.