Dahl al Hamam Park is close to Landmark shopping mall, in the intersection of Arab League Street and Al Markhiya.

It's not in the Al Saad Area, but it's nice at night, has a restaurant (fast food) and plenty of space for kids to play. Basketball court, an open air theater, playgrounds for small children...

I've gone there many times for a night stroll/jogging and find it nice.

Plus, not many people even realise it's there, and it's normally quiet.

I haven't seen BBQ facilities, I'm afraid.