Empty Launchpad completely—removing even Apple’s own apps. The crux of this trick is wiping out the contents of the database Lion uses to know what goes where in Launchpad. To do so, launch Terminal (which, as always, is in /Applications/Utilities) and paste in this sequence of commands at the command line:
sqlite3 ~/Library/Application Support/Dock/*.db "DELETE from apps; DELETE from groups WHERE title<>''; DELETE from items WHERE rowid>2;"; Killall Dock
Now, open Launchpad again. It’ll be as blank as the faces on those guys in Apple’s 1984 commercial. Of course, if you purchase an app from the Mac App Store, its icon will show up in your newly naked Launchpad.
Getting the apps you want back into Launchpad is simple: You can just drag the apps you’d like to add directly onto Launchpad’s Dock icon. (Merely dragging icons onto the Launchpad icon in the Finder won’t work; you must drag onto the Dock icon.)
Miss the old, overstuffed Launchpad? You can get it back by forcing Lion to rebuild your Launchpad database with this Terminal command:
rm ~/Library/Application Support/Dock/*.db; killall Dock