Probably a few times a day, depending on what I'm doing.

I work in a small office, and answer the phones. Most of the time the call needs to be transferred on. Standard operating procedure if someone can't take the call is to say they're "unavailable, can I get them to call you back?" and, if pressed, "on another call at the moment". This is usually untrue - we don't get many calls, so 99% of the time it'll either mean they're in the bathroom, having lunch or just don't want to talk to an overly needy client who keeps calling at the moment.

I'll often also lie about my position if a client questions why I can't handle their call. It's easier to say I'm just the receptionist or something isn't my department, than explain why this either needs to be handled by someone else or would be far cleaner that way.

Oh, and I lie about why I'm putting people on hold all the time. I'm often not bringing up your file or whatever - I did that while we were talking.