HEY EVERYBODY! Credits to ccamm who told me about this secret message in the newspaper on the first page. Click on the NIN in the lightning then the J in the dojo and then the first A in damage in the title. Here is the message that pops up.

I found out that training begins next monday because the sign said so!

There is a secret ninja poster that only pops up when you do this:

Click on the lights under the stairs one by one starting from the one on the top left. Then click the wear a hard hat sign and then a ninja poster should pop up.

 Sorry the picture wouldnt come up but is a picture of a ninja. A bit different to the ones that were on penguin chat 3.