At my grandma's 50th party, my mom and her sisters had a huge surprise party where they rented out a room; filled it with quotes from the (hilarious) diary she kept while raising them (they were very bad); enlarged pictures of her; stuck her in a wheelchair with an IV filled with vodka; and had all sorts of friends from her past and present filling the room to make fun of her and love on her. It was a sweet idea to make her feel special.
My mom loves Hawaii, so for her 50th she did a Hawaii party where she rented out a space, filled it with decorations and food, and invited all her friends.
I guess those ideas are for folks who like a big thoughtful party having to do with who they are or what they like. If you want a small intimate restaurant...hm. Hopefully someone else has ideas.