[moocowduckquack]

<5k arcade games with download progress increasing the difficulty might be good for some sites.

[chrisballinger]

Unfortunately, this was patented by Namco in 1995: http://www.google.com/patents/US5718632

[mistercow]

So sad, it would have expired last year if it had been filed only 6 months earlier.

[moocowduckquack]

The claims in that patent are in terms of main games and auxiliary games. If your main site content is not a game, but you just use a very simple arcade game while loading, I am not sure this would apply.

Also, the claims seem to be for the situation where the progress made in the auxiliary game is then reflected in the main game, if the loading game is merely a reflection of the loading process itself and is not related to the main content, then it would seem to be fine even if the main content is a game.