A relatively unprofessional one — like mine, for instance — does the opposite: It encourages prospects, recruiters, and potential connections to run in the other direction.
Funny voicemail greetings are just that. These types of greetings have no rules whatsoever. They’re just for funsies, so make those you care for the laugh. Most of the time, they are personal, but certain businesses can use them as well. Perhaps you operate a theatrical costume company that specializes in clown memorabilia, or perhaps you run a business that sells pranks, such as plastic puppy poo, and whoopee cushions.

Great question! Although I don’t know if there is a specific function for this on your particular phone, the best way to save the message is the simplest. Turn up the sound as high as you can and record it onto a digital recorder (like you would use for a lecture), a cassette recorder or your cell phone if you have a voice recorder on it. Then save it as an MP3 on to your computer for safe keeping. You can also Google your vtech model number to see if you can find an owner’s manual. They might have a way to save a recording in there. Probably not, but it’s worth a shot.
My wife and I can’t come to the phone right now, but if you’ll leave your name and number we’ll get back to you as soon as we’re finished.