The genius that was Amy Ryan's Holly beatboxing on The Office last week got me thinking about other cast additions that have made shows better. The first that came to mind was actually another Amy Ryan role -- Beadie on season two of The Wire. It took awhile for me to get into the whole dockworkers storyline, but it was Beadie that helped me through.
If a show plans to stay on air for awhile, it needs fresh blood -- but the process of introducing new characters isn't easy (witness how reviled Maya was on Heroes). The best new additions combine great actors with well-written characters.
Here are seven other (fairly recent) new characters that succeeded.
A long time ago, on an Internet far, far, away, the creators of the NBC series Heroes decided that a weekly webcomic series would coincide perfectly with the show they were producing. I mean, Heroes is about superheroes. So, during the first season of the show, a different artist penned a short webcomic (about five pages long) that focused on the background of one of the characters, or introduced a new character not seen on the television show. Eventually, all 34 chapters of this webcomic were collected and 
Six Mad Men characters who are in limbo after the finale
Fact or Fiction: Big Bang, Brothers & Sisters and CSI
The TV Squad Podcast: Linda Purl talks about The Office, we talk spoilers, and more
