Use the time to catch up on work
Use the time to bone up on Perl
Use the time to goof off on PerlMonks
Eat a lot of pastries
Time? What time? I have work to do!
Invent some work to justify yourself (consultant)
Clean everything in sight
Play nerf football with the network guys in the hall
Craft cunning booby-traps for your missing coworkers
Finally get around to writing that killer module you've always wanted to
Zzzzzzzz....
Do something else