If you want to go simple and since it is sooo hot, I was going to suggest a BBQ (hotdogs, hamburgers) but if your DH is like mine, than that is more his area and therefore would not be much of a surprise. 
Other easy things are lasagna (or spaghetti), salad, bread, dessert or you could have a taco bar with all of the fixings or what about ordering a chicken finger and/or wing platter and then have a veggie tray and some potatoe salad, baked beans, bread, etc?
There is also always pizza. Doesn’t get much easier than that!!