I love my Google Voice number, as it gives me a lot more control over who can reach me on the phone. Unfortunately there are instances where I hate even giving that out, as I don’t want some people being able to contact me in the future. For those instances, there is an awesome free app called RingShuffle.
Install RingShuffle on your iPhone (sorry, no Android version right now) and create an account. This consists of entering your phone number, email address, and setting a password. Then you just pick your temporary number, and you’re all set. You can even specify the area code you want (it defaults to the area code of your current phone number). For the next seven days, any call that comes to that number will be forwarded to your phone. After that, it goes back into the pool of available numbers. Not too bad, for a free service.