iOS: You can technically hail an Uber for someone else already, but it can be a long, frustrating process. Teleport on iOS makes it super easy to hail an Uber for someone else and have them delivered to you. They don't have to sign up, download, or pay for anything.
Teleport, created by Michael Wang, Victor Wang, Eugene Yee, and Bob Wu, uses Uber's API to let you hail a ride for anyone you have in your phone's contacts. There are no downloads required on their end, and you can send them anywhere you like at no cost to them. You can invite a frugal friend to meet you out for drinks, impress a date with their own driver to take them to your surprise meeting place, or make things easier for an elderly family member who has a harder time getting around.
You have to sign up to send a teleport request, but once you do that and link your Uber account, you're ready to go. Select someone from your phone's contacts and you'll be able to add a message and photo to your invitation, select the address you want to send them to (it defaults to your current location), and decide between all of the different Uber services they offer. Once they accept your teleport request, the Uber will be hailed to their location. Keep in mind, however, all fares and ratings will be applied to your Uber account.
Right now it's only available on iOS, but the apps creators say that an Android app is on its way and should be available by early 2016. You can download the app at the link below, or learn more about it at their web site.