Seriously, Web of Power/China, Hansa, Paris Paris, Hansa, Zooloretto, Patrician and California are all standbys in my collection and fit that time bill. While I know Schacht has made heavier games, for me, he is a master of quirky, medium light games that are engaging and thought provoking.
Unlike Knizia or Kramer or Teuber, I didn't have a sense of Schacht as a designer for a while. However, thanks to Paris Paris and Web of Power being on BSW, he was part of my initial gaming experiences.
His games kept finding their way into my gaming experiences and collections (and I don't think I have ever culled one of his games out of my collection) but it wasn't until Patrician that I put together how many games I liked were by him. Which is kind of ironic because I would say that it's the weakest of my personal Schacht collection.
Unfortunately for me at the moment, pretty much all of his games in my collection either play better with three or more or flat out need three or more. And we're currently a gaming group of two :D
Still, one way or another, be it the toddler getting old enough or finding other parents who game, we will be three or more again. And then, these games will shine.