Show HN: "Never wait on hold again" service built with Rails and Twilio 
And if you were a forward thinking megacorp, you could build something like this yourself.  "Hiya, this is Paypal.  Hit 1 to talk to ...  Thanks.  Type in your last four digits of your...  Thanks Mr. McKenzie.  Would you prefer to hold while waiting for a representative, or should we call you back in approximately 15 minutes?  Hit 1 to..."15 minutes later."Hello, is this Mr. McKenzie?  Hiya, this is Steve at Paypal and I have your account brought up.  What can I help you with today?"I think that's far, far cheaper than $100k in dev costs and, if a 6 week test eliminates 5% of your CS spend while bringing your hold times down by 50%, that's like a career-making win.  (Seriously guys: Twilio is the startup to watch.  I say this while I'm literally wearing their sweatshirt but trust me, they're going to be massive.)P.S. After you have it, you can trivially wire it into click-to-call on your webapp.  "We can't show you that transaction, due to routine procedures meant to protect your account.  Click here and type in your phone number, and we will have our Security Team contact you in the next five minutes.  Thanks for using Paypal."