The last three places we've lived in South Florida were "gated communities" which is supposed to make you feel exclusive and special.  They provide zero additional security (had a car stolen from one of them in the middle of the night) are often broken, and even when they work they're a pain.  All of our gated communities would link your personal code to a phone number of yours, and when visitors keyed in "112" it would ring your phone. This causes problems:

• The gate dialer can only link to one phone.  If your wife is traveling and you want some pizza to be delivered, the wife may not be able to pickup the phone and press 6 to let the pizza in.
• Most can only link to one or two area codes.  One of the systems could only link to a 954 area code number.
• If you're riding with someone else and don't have your remote with you, you can't get in if your wife isn't with you, or has the cell phone in a bag in your trunk.

The Wife has been out of town for a few days and this finally irritated me to the point where I headed over to Tropo.com and provisioned a simple phone application.  Now when you dial the phone number of my Tropo app, it answers, says "Opening the Gate!" and plays a number 6 key press which tells the gate to open.  Perfect. I heard about Tropo out at CodeConf in San Francisco and have wanted to play with it but didn't have a problem to solve until now.  The entire thing took about 10 minutes to setup with the only really painful thing being the hunting down of a key press sound from http://www.freesound.org/ and the subsequent conversion to a GSM format.  I ended up using the excellent Sox command line sound converter to make the conversion, and then we're in business.  Total cost for the whole thing was zero dollars. The Tropo service is really nice and their documentation is good too.  Their UI for their website is a little clunky in spots.  For example, picking an area code for your number is really painful with about 50 city suggestions and no way to search for an area code or specific city.  They're not alphabetized as far as I can tell either and the city names are super specific so it just makes it hard.  Also, I couldn't find a way in their API to generate a key press tone which meant I had to mess with my own sound files.  That should be built right in or they should provision a directory of key press sounds with your default files. All in all a fun little project to get done while on Amtrak bound for Orlando, and now I can open my gate whenever I want.  Tropo has done a great job with their platform and I'd highly recommend it for these types of tools or any kind of telephony or communications application.