I know this a really hard to do with a bad experience under your belt, but I would also suggest being upbeat about whatever stuff he brings home even if you think it is the lamest thing you have ever seen. I've said my share of noncommital comments like: "Well, let's see now. Pretty interesting. I'll be interested to see how that turns out" when thinking something far harsher! Especially since you son is having a good time, there is no reason to let your anxiety taint if for him.