Informal:
Would you like to . . .
We're going to . . . . Would you like to come along?
There's a . . . . (tonight). Would you like to go?
How about (V+ing) . . . ?
Do you want to . . . ?
I wonder if you would like to . . .
I was wondering if you would like to . . .
Formal:
I'd like to invite you to . . .
If you have time, I'd like to invite you . . .
Would you like to join us for (event) at (time) ?
We'd be glad to have you accompany us . . .
We'd be delighted/honored to have you as our guest at . . .