First off, you get on every website you're a member too and complain about no one being on anymore.
Then, you actually contribute something useful to said websites.
Then, with a group of friends, you cast off your regular outfits and reveal your true colors: the Totally Awesome People Crew!
(Note: if you and you're friends aren't part of the Totally Awesome People Crew then become part of it.)
Go swimming in the lake/river/ocean/swamp/pool closest to your house.
Call all of your closest friends cell phones and, when they answer, ask if you woke them up.
Go to 7-11 at 2 in the morning, get slurpees (the biggest ones) and then proceed to nearest park with a baseball diamond and sit on top of the dugouts.
Throw a huge party.
Read a book.
Take a bubble bath.
Go on a nice walk.
Organize your computer desktop and My Documents folder.
Time travel to see what actually killed the dinosaurs.
(Note: try to get back before said event happens)
Time travel to stop the birth of that annoying kid who sits in the back row of your homeroom and won't leave anyone alone.
Just plain time travel.
Teach an old dog new tricks.
And, if there's time, sleep.