Oh, this is a fun site. What Spoofcard.com does is allow you to block your telephone Caller ID and disguise your voice. Apparently they offer a service for folks who like to play practical jokes on their cellphones.
No, not really. Where this would come in handy is if you want to display your company phone number when making business calls from your personal phone. You can record the calls and play them back from spoofcard.com’s web control panel. Very nice!
If you aren’t into putting together a 555 timer and a comparator for a barebones audio distortion circuit Spoofcard.com could be a lot of fun.