I like to leave Gaming open on the front page and watch for new questions. Tonight, however, I wound up watching my reputation bar instead, as it was doing something odd.
Essentially, every time you get an upvote on one of your answers, your rep counter increases by 12 instead of 10.
Did some testing with Dennis on MSO, and not only is this bug no-repro on Stack Overflow, but the dropdown updates properly to boot!
When you refresh the page, your rep recalcs, and displays the proper amount again.