"Over the Hill" as a birthday party theme is often listed under 30th birthday party ideas, but can be used for 40th, or even 50th birthday parties as well.
A 30th birthday is the major milestone where you are perceived as being “older”, but you are really, truly not “over the hill”!
Party stores sell lots of fun Over the Hill accessories, such as walking canes, funny hats, yard signs and buttons.
Make sure you decorate with lots of black balloons and streamers! You are "in mourning" for their youth. So black is key.
Dancing? Play some old retro hits. The oldies but goodies!
Another fun thing to do is to ask guests to bring small gifts that an elderly person might need. It is always funny to see their reaction as they open these things. Some examples might be...
For a fun cake, make a graveyard cake, complete with tombstones!
Different Over the Hill and Birthday Cake Themes:
Do you want a fun idea, but still a little different? You could also do a Western Theme Party and make your cake a "boot hill", complete with a tombstone for the birthday person!
Another idea is to incorporate dinosaurs, since the birthday is celebrating someone "from the dinosaur age."
Ever hear the expression that someone is "older than dirt?" Throw in a gardening or outdoor theme! You can serve a Dirt Cake