If I ever took the time to make a list of words I always misspell, "indefinetly" would top the list. You know, it's very similar to "define". And yet, means something else entirely. It has that tricky "in" prefix, which works so nicely in other words - like indistinct, inconsequential, and so on. Then, just to make life interesting, we throw on the "tly" and PRESTO! a word that means "pretty much always not defined". You know, something like that.
I broke down earlier today and Googled "indefinetly" after trying at least 2 or 3 other (incorrect) spellings. I cringed, hit Enter, and could practically SEE Google smirking at me in the Did you mean: indefinitely link.
Yes, I meant "indefinitely" ...you bastard.
PS - First canceled ("cancelled" would also make the list) flight of the season earlier today! I'm giving December a slogan: Winter '08-'09: Off to a Strong Start.