Nope. The show was picked up for a 6th season not too terribly long ago. Plus, from what I have seen, it seems like the show only continues to get more and more popular.
-On a completely unrelated not, the press release/synopsis for "Twin Beds" is intriguing.
Edit: For anyone that wants to read it, just go to the HIMYM Season 5 Wikipedia page. The links are in the footnotes.
Firstly, that concerns me (the twin beds synopsis) but it also makes sense to what I think this entire seasons about. We haven't seen much growth at all, but it makes me feel like it's all a build up to something, the Narrator Ted is building up to something or trying to put off telling a story because he's worried that without the correct groundwork it will sound bad or cast him in a bad light.
Plus, it's not the first time he's talked about other people incessantly as a build up to his own stories. Normally it just takes place over one or two episodes.
I think until I can watch this season in its entirety on DVD I won't appreciate it properly, but also there have only been 4 or 5 episodes that really progress the story in any way. So either they better bring it in the next few episodes or we need some serious shocks at the end. At least much better than season 4's ending, The Leap was a great episode but not a season Finale.
EDIT: also, much excitement about next weeks episode. Mostly because of this: 10 year Old Marshall................ Koby Rouviere; Marshall flashbacks are hilarious