It's my fourth batch of beer and after racking I had my airlock overwhelmed with foam and beer. Thinking it would be a good idea to remove it, I took it off and was blasted in the face (as was a good part of the room) with beer and the recently added blueberry puree. Yum.
I rigged up a blowoff tube using my racking cane and a pot of sterilized water and the whole thing is sitting in the bathtub until it calms down.
I'm lead to believe from reading this forum that this is a pretty common experience... too bad it had to happen to me the first time when my carboy had dark colored fruit in it!
The blueberries I added appear to have contributed a fair bit of sugar because the fermentation is going really hard in the secondary.
I just hope nothing got contaminated in the process.