Mine are 16 & 10 now, but at four (I remember it well
) we lowered our expectations somewhat.
They both sat and didn't run around, I was lucky in that respect, but when they started to get bored and fidgetty - we also did some mild entertaining as a family, such as the a-z games (taking it in turns to think of an animal beginning with 'A' through to 'Z' - ach you know it!)
Or the memory game - I went to the shops and I bought...
And I- Spy! Theres nowt like playing I - Spy with a truculent 4 year old who insists that 'ceiling' begins with an 'S' - and the fall out from the 10 year old who sounds like a 5ft Jeremy Paxman correcting him.
We didn't do this all mealtime, cos they were happy to chat for lots of it, but it was a handy standby!
Having said that - I've had the odd meal with elderly parents/in-laws etc, when aunty muriels hip operation has been discussed at length, but they have also joined in a game of I-spy when the children were very small- and it's been hilarious!
Oh - and YY to kids menu's - sausage 'n' chips - sometimes they want that - great! but they much prefer having smaller portions of the proper menu they can have.