I checked in a mass of code for the project that I've been working on so that other people would have access to it to add their bits. It's on a branch, so I wasn't too worried about it.
Then I ran one more test and found a nasty serialization error. So I fixed the serialization error and checked in the fix.
I'll have to clean up *my* test data, but at least I haven't contaminated anyone else's data. :)