I don't think there's one formula or one "right" way to ask. It's totally going to depend on the circumstances of your job, hours, boss, etc. I just recently switched jobs, and on my first day, my new boss took me out to lunch and we talked about all the personal stuff (family, hobbies, stuff like that) that they can't or don't ask during interviews, and I told her about my involvement in this group. She got a kick out of the whole thing. Since then, I've had no problem taking time off for trooping stuff, and she's always asking about what we're up to. At my old job it was the same way; they were pretty lax about us taking time off as long as we got our work done. But really it depends on your own circumstances. I'm lucky to have a Monday-Friday, off by 4:00 p.m. job, so for the most part it doesn't interfere with trooping.