RideTones is a toy / gadget / pure-gimmick that basically consists of a brain unit and a separate speaker which are installed into a car; when certain electrical system events happen, such as locking the doors or rolling up a window or popping the trunk (up to 16 different events, depending on the installation), RideTones plays a user-specified noise in response. To me the whole idea is like applying Windows sound themes to your car, but here's the kicker: you need to pay for the audio content, just like cell phone ringtones.
At the time of this writing the website (www.ridetones.com) offers a seemingly extensive collection of sounds, but once you start digging it's pretty obvious that all the content comes from one of these cheap royalty-free libraries. This isn't much of a limitation though - for the same price as a regular download, you can use the provided 'create your own tone' service to convert any audio clip you supply into a tone.
I suppose you could have some fun with this - there's the obvious cheesy ideas, like having the knight rider theme music play whenever your car starts up, but I'm sure a careful user could come up with more subtle and sophisticated treatments. It's certainly not something for everyone, and the company is probably right in targeting the tuner and tuner-wannabe types: West Coast Customs (www.westcoastcustoms.com) has started advertising the product heavily. At a price somewhere around $200 US (installation not included!), you need to be pretty serious about customizing your car before you'd consider buying this.
How long will it be before you start seeing - or rather, hearing - these things in your neighborhood?