My favorite idea is to go along with whatever the host or hostess is already doing.
If they're needing to work in the garden, I want to do it with them.
If they want to go to a hockey game, then that's what I want to do.
If it's just sitting around and talking, then that's great.
I'll help wash the dishes, sweep the floors, whatever needs to be done to spend time with my family or my friends.
The only big thing I don't suggest is spending a lot of money.
It's the time spent together doing something productive or useful, or even mundane, that creates a lifelong relationship and memory.