One of my client's websites in which no funny business was used is now cached as a blank page by Google. The rankings for the site were decent and climbing steadily (bottom of page 1) and now he is gone. Does anyone know what is up? Another client has the same problem on one his flash pages. Both sites are unrelated no cross-links to each other. Anyone?

It happens from time to time, server glitches, different DCs etc.

Is it a new site ?
has there been any server downtime?

wait a while and it will probably be back at the next indexing of the page. When it's been more than a month then worry.

It has not yet been a month. However MSN is also caching a blank page as well, though MSN is not dropping the rankings. My guess would be that the server timed out. I was making sure no one else had seen this with Jagger.

It should all return in a month or so, like Chris said, after the next indexing.