I’m not sure how much of a spoiler it is but according to tvline the title of the How I Met Your Mother Season 6 Finale is, wait for it….

…. still waiting?….

“Challenge AccepTed”

Here is the full Q&A from there on HIMYM:

Question: Is How I Met Your Mother going to show us the “Mother’s” face in the season finale? Or are they going to make that the cliffhanger? —Matt
Ausiello:
No idea. I bet if we knew what the title of the episode was we could extract a clue or two from it. THIS JUST IN: I can exclusively reveal that the title of How I Met Your Mother‘s sixth season finale is… “Challenge Accepted.” What does it all mean? I believe that’s what God invented comments sections for.

Question: Tell me something about How I Met Your Mother that doesn’t involve the mother or the mystery wedding. —Jill
Ausiello:
The gang will suffer another devastating loss later this season. Hint: For the past six years, it’s been more up-close and personal with their privates, in particular their butts. I’m talking about their booth at MacLaren’s! A new group of friends enter the pub and steal their coveted perch. Cue World War III.

Does that mean anything to you? Could it provide clues to the wedding, the mother, Barney, Robin? What coudl it all mean?

Use the comments section appropriately.