The Jacques Mckeown books have been very entertaining so far. I'm irritated that Audible is paying him to make them timed audio exclusives, but what can you do? Douglas Adams was my favorite author so I don't use the comparison lightly. Slight complaint, Yahtzee loves the word nacelle

A personal Scalzi recommendation would be Kaiju Preservation Society. It's short, shows his humor pretty well, and should give you an idea if you want to start his books. Personally I didn't find Old Man's War to be his best work