I have to hop

The line one rolls out when one can no longer bear an all-hands conference call, but there is no less brazen way of engineering an exit.

It implies you have something better to do — let’s face it; it's a matter of irrefutable mathematical logic that one has something better to do — even head-butting a filing cabinet would count — if what one is currently doing is attending a conference call: — but doesn’t commit you to articulating anything upon which an unemancipated fellow participant could pass judgment.

There are more or less snarky variations of this expression, the best of which is “I have to hop: I have an industry call starting” — the office worker’s equivalent of “I’d love to stop and chat but I have to go and wait in the lobby”