SnowLeopard.
I commonly use copy in a terminal window to grab stuff I have to paste. A few times in the last few days, the clipboard has gotten 'stuck' on some old text. I do the copy gesture (with keyboard or Edit menu) in the terminal window. I paste somewhere else, and get something other than what I just copied.
If all else fails, I can always tell the terminal to write it's content to a file and use that. But I'm wondering if there's something I'm doing to get into this pickle and if there's any way out.
EDIT
This seems to be provoked by having a great deal of history scrollback on the particular tab. Sometimes the next thing that happens is that Terminal crashes.