As said in the additional information, these are websites which people claim are unblocked to schools. Some of them are even "unblockable"!! which is pretty amazing...although, don't get your hopes up because it really just depends on the school domain. But anyhoo, hope this works for you! 
Only bit of advice I'd say is...if you're at school, make sure you turn your monitor slightly so the teacher can't see it so well. Or another trick is have another tab open (have it on Google or some other casual website which you're allowed to go on) and when the teacher comes round, switch to that tab and then minimize the browser so if the teacher looks at the wee thing at the bottom of the screen, it will say "Google" and none of the other tabs =D
Happy playing games, wasting time and not doing work when you're meant to! 

Cool Maths Games

Picture

Minking

Picture

Some School Games

Picture

Physics Games 365

Picture

Bored2fun

Picture

Funhour

Picture

Dusty (I'm not 100% sure it's called this but who cares?)

Picture
http://dustyb883.webs.com/games.htm

I did not find an image for this website due to it being an unofficial website with no logo or whatnot.  

Free Webs

Picture

Oacie

Picture

WR - Games

Picture

Super Tight Stuff (okay okay, ignore the name...)

Picture

Picture
Follow the company: Schevensteiger, who created this website for your benefit, on Twitter. Click here to follow Schevensteiger.