My MacBook Pro doesn’t feel good

About half of my applications suddenly started “beachballing”, when trying to shut them down they did not. I killed them and could not restart them. Looking at the logs I saw this:

May 20 11:51:47 TwinPower diskarbitrationd[146]: iCal [8351]:26247 not responding.
May 20 11:51:47 TwinPower diskarbitrationd[146]: RescueTime [29391]:34011 not responding.
May 20 11:51:47 TwinPower diskarbitrationd[146]: Safari [29406]:23663 not responding.
May 20 11:51:47 TwinPower diskarbitrationd[146]: Quicksilver [302]:24079 not responding.
May 20 11:51:47 TwinPower diskarbitrationd[146]: Groupcal Daemon [308]:23043 not responding.

It doesn’t look like a good sign…