SEASON PREMIERE: This durable, truly amusing improv series begins Season 13 tonight, with Aisha Tyler as host, and with regular class clowns Ryan Stiles, Colin Mochrie, and Wayne Brady having fun with props, suggestions, and each other. One thing that’s laudable about this series, especially on a holiday evening: It’s a perfect show to watch with the entire family. And these days, there are fewer and fewer of those all the time.