My husband's 50th was last year at this time. I had a catered party at our house. We invited about 20 people, so it wasn't huge. It was so nice not to have to worry about cooking, serving, and cleaning up. People brought nice, but not extravagant gifts. The best thing was that our son was home from the Marines for this.
The party was actually a couple of weeks after his birthday. Two days before his actual birthday, we did a century and (foolishly) went out that night to a very nice restaurant and drank too much champagne.

We usually do bigger things for "0" birthdays.