I'm not much help for my 40th DH got me a man.

Okay I didn't get to keep him, he is a guitar player / singer friend of ours who performs in Hilton Head DH hired him to come play at my party. When I walked in he was playing one of my favorite songs which he had just learned for me that afternoon !
For DH's 40 I rented a cottage in Key West for two weeks, along with a
scooter, we didn't even have a car. It's been our best vacation ever !
I like the idea a pp had about having people over and having the meal catered, catering might be cheaper than you think, with a fancy cake and champagne after dinner. You could do a fun theme, you know going back to your childhood, do a Disney theme, or Birthday hats, and games. OR since it's winter go totally out of season and do a Luau theme.
This year I did an unBirthday Tea Party with odd foods, a mixtue of regular and vinegar potato chips in a hat box, animal cackers in a dog food bowl, a big punch bowl full of cheese balls..... you get the idea. It was a ton of fun to come up with.