well a lot of them has free games – the problem is that a lot of them work like crap.
For example most of the Microgaming once now require the player to download some activeX stuff on their computer to make it work properly. That kind of defeats the purpose of a no-download game in my opinion.
As far as I know the only place who offers a few games that actually work as they are supposed to is Referback (offers a few shockwawe powered games) and Partnerlogic (slots,roulette and BJ).