In the past week, I think meta has been vandalised every day, around 4 or 5 in the morning GMT+2. When no one is around, the vandal bot is really giving a lot of clean up work afterwards. Please, drop on meta from time to time to check situation.
Note : how to recognise there is a problem : usually, what you will see is this :
# (diff) (hist) . . Linguistic democracy in a multilingual project moved to Iiiiiiiiiiiiiiiiiiihhhhhhhhh; 05:15 . . Lavoii (Talk) # (diff) (hist) . . Talk:Wikipedia drop-outs moved to Talk:Ddddddddddddddvvvvvvvvvvvvvvvvvvv; 05:15 . . Qoqucof (Talk) # (diff) (hist) . . Wikipedia drop-outs moved to Ddddddddddddddvvvvvvvvvvvvvvvvvvv; 05:15 . . Qoqucof (Talk) # (diff) (hist) . . Running MediaWiki moved to Ppzzzzzzzzzzzzzzzzzz; 05:15 . . Yepolod (Talk) # (diff) (hist) . . Talk:Wikisource moved to Talk:Ddddddddddddddxxxxxxx; 05:15 . . Iire (Talk) # (diff) (hist) . . Wikisource moved to Ddddddddddddddxxxxxxx; 05:15 . . Iire (Talk) # (diff) (hist) . . Talk:Wikipedia sociology moved to Talk:F; 05:15 . . Iovutowo (Talk) # (diff) (hist) . . Wikipedia sociology moved to F; 05:15 . . Iovutowo (Talk) # (diff) (hist) . . Documentation:Administration moved to Rrrrrrrrrrrrrrrrrrrffffffffffff; 05:15 . . Oekisa (Talk) # (diff) (hist) . . Liste des wikimédiens francophones moved to Ccccuuuuuuuuuuuuu; 05:15 . . Vuuo (Talk) # (diff) (hist) . . Articles on fr with no interwiki link to en/Q moved to Nnnnnnnnnnnnssssssss; 05:15 . . Miju