Ping has an app called PING® (with the registered trademark symbol) on the app store. Not sure if the official name is PING or PING®.
From the article:
IM-style email app Ping is now called Hop after a naming dispute – with a golf club company
Ping, the app that reimagines email as an IM-style activity (read our full review) has today relaunched under the name Hop after receiving a cease-and-desist letter from the maker of Ping golf clubs.