We are planning some maintenance at 05:30am UTC on Monday 26 Jan 2015. We will have to bring down some services in order to upgrade them and that will (obviously) affect our functionality.
While we expect it to last no more than 30 minutes, we are giving ourselves a maintenance window of one hour (that's mainly because it is going to be early morning in our timezone and we are known to be slower than normal before coffee runs down our physical systems).
So if you're an early bird coder in Europe or a late night maker in the US, give your self some some time off during that period.