There's almost always a "final stage" event now that's usually when a series is very near finishing airing (or right after it has finished airing.) These tend to have the actual actors appear in the show itself as well as the Q&A afterwards, unlike most of the stage shows which run during a series. Those are usually just people in suits, and in some cases like the Super Chara Festival events, there are actors/actresses, but only after the show is over and they're not directly involved. There's a couple rare cases where they get older actors to appear; I know Fujioka & Miyauchi were in a big outdoor one around the time of Ryuki or Faiz. That would've been cool to see.
Getting tickets for these sorts of things usually requires you to be in the country, and either get them at a convenience store (7-11, Lawson, Family Mart, etc.) or get them online and have them sent to a Japanese adress.
Locations vary, but they're always in the big cities and I'm pretty sure the final stage ones are almost always in the Tokyo area.
As for meeting the actual actors, that's the tricky part. Getting to shake hands with guys in costumes is easy, with the actors themselves, not so much. It's not completely impossible but it largely depends on the event; at a convention or a signing you've got a good chance, at a big stage show or event aimed more at families than adult/older fans, you'll probably get to see them on stage and *maybe* be lucky enough to ask a question (especially if you happen to be a Japanese kid under 10), but that's about it.
I will say this though: if you are lucky enough to get to see actors at a big event/stage show and you're close enough, try to be overly enthusiastic when they leave because that's when they take a little time to wave/interact with the audience before being spirited away. When I got to see Satô Yuuki and Katô Kazuki back in January '07, I made sure they saw me. :anime:
And you always *might* just be lucky enough to run into them (and their entourage) before or after the show/event.
