Some friendly person is leaving or has left several alarm clocks around in the periodical stacks and various places (I’ve found two and Jason has found at least one other). They seem to be set to go off between 1:30 and 3:30 PM. This ranks up there with the crickets someone left in the third floor stacks a couple years ago.
But, we can make use of alarm clocks left as “practcal jokes” which, sadly, could not be said for the crickets.