PayPal has updated its Android client to allow person-to-person transactions by tapping phones together, but without the complexity everyone else is using.
Finally you can borrow an electronic tenner at the bar, just by tapping phones together. Assuming you both use PayPal, and have NFC-capable Android, handsets, and have the latest PayPal app installed – and that the pub has decent network connectivity too.
PalPay's system only uses Near Field Communications (NFC) to identify the payer and payee; all the security and account information is held in the cloud. So both parties will need to be online for the transaction to work. But if they are – and both have Android handsets with NFC support – then one user just requests the cash and the pair tap phones, the other user authorises the payment and ... Bob's your uncle.
PayPal is still pretty lukewarm about NFC, as it (quite rightly) fears being locked out of the secure element which underlies all the other NFC-based payment systems. The secure element allows offline transactions – and fast transactions too – but it is becoming clear that it will remain under the control of the existing players (Visa, MasterCard, etc), which doesn't fit with PayPal's "disruptive" agenda.
So NFC is restricted to exchanging account details, but you can use it to move money between PayPal accounts. Now all you need to do is find a bar which will let you use that borrowed tenner to buy a pint or two – good luck with that. ®