The first third-party applications for Dash's GPS (you know, that internet-connected smart GPS) are here, and they do some interesting things. There's Trapster, which shows you whether there are speed traps ahead (and let you contribute trap information), Mediaguide, which shows you the last three tracks played on any FM or AM station, and WeatherBug, which tells you weather conditions now and later.
Other slightly less useful apps are Coldwell Banker's real estate search—only useful if you're actually looking for houses and like driving around aimlessly hoping you get lucky, and Funambol's calendar feature, which checks your calendar for appointment locations. Trapster is free, but we're not sure about the other apps (they may not be).
A commenter notes that some apps are limited by the UI. The Trapster app makes you keep searching for speed traps instead of just displaying them constantly on your UI. [Dash]