1. Wave. A friendly wave can welcome someone into your office without fear of spreading germs.
2. Share some hand sanitizer. Hand sanitizer has become the new gum. In that you share it, not that you should put it in your mouth.
3. Salute. Will it look awkward? Absolutely. But will everyone get a laugh? Yes, indeed.
4. Tip your hat. This, of course, means you must be wearing a hat at all times. But who doesn't like feeling like an old-school private investigator?
5. Live long and prosper. Those of the more nerdy inclination might favor Spock's iconic hand gesture, which is friendly but requires no touching.
6. Air high-five. The best thing about an air-five is that you can do it from six feet away. Nailed it.