Reaching 100 episodes is a milestone for a television series because it means the show has attracted enough viewers to last at least five seasons.
Only three live-action network comedies on the air now have reached the coveted goal: "Two and a Half Men," "The Office" and "How I Met Your Mother." The first two aren't a shock because they've had ratings success and critical acclaim.
The success of "How I Met Your Mother," which hit the 100 episode mark Jan. 11, is a little surprising. Its ratings have been good, not great. And, except for a 2009 Emmy nomination for Outstanding Comedy Series and a few Emmy nods for star Neil Patrick Harris, the show has earned marginal attention on the awards circuit.
"How I Met Your Mother" has chugged along — a steady provider of laughs and giggles through quirky characters, an odd storytelling structure, offbeat musical numbers and a consistent level of solid comedy.
Even CBS executives have spent little time thinking about the show.
"I was on another sitcom before where they would radically change things. There was a lot more network and studio involvement and they were much more concerned about its success, and so there would be a whole new show the next day, sometimes," Harris says during an interview on the set of the show. "The studio and the network have been relatively hands-off."
The network has allowed Harris and the show's merry band of lunatics — Josh Radnor, Jason Segel, Cobie Smulders and Alyson Hannigan — to show just how funny a group of friends can be.
Their antics have played out against the long-running narrative provided by Bob Saget who has, since episode one, been telling his children in the not-too-distant future how he met their mother.
That element has had less importance in recent seasons.
"There are episodes where we don't touch upon it at all. It's the story of Ted and his friends and that second sort of adolescence of late 20s, early 30s and entering adulthood," says Craig Thomas, the show's executive producer and co-creator. "To us, there's so much more to talk about than that. But it's great to sort of like have that up our sleeve when we want to, and it's given us a lot of great ideas and a lot of different kinds of stories that we can tell."
The show continues to create fun moments with its offbeat structure. Along with the narrative, the show often features multiple views of the same scenes, fantasy sequences and even a few musical numbers.
"I think it's especially important for us to think outside the box, especially in this day and age," Smulders says.
And that thinking has caught the attention of the CBS executives who have already decided the comedy will be on the 2010-2011 schedule for a sixth season.
As for the mystery of meeting mom, look for a few clues but no big reveal until the series finale nears an end.