There are some vandals going around and defacing all the pages. Once they have been blocked, we need to restore the pages to their former glory using previous revisions. However, until they have been blocked, any attempts to undo vandalism will be quickly undone, so I would advise that you click the arrow by the Edit button, then click on History, and go view an older revision from before the vandalism for each page you want to read.
EDIT: Looks like the situation is under control now. Have a nice rest of your day.