Hey, Rapidshare can tell if you've downloaded in that hour because it looks at your DNS servers. Your computer's lease on a DNS server expires every week. If you catch it at the right time, you can download something before your server changes, and download again after it changes. Of course this can't be done every time, (only once a week) but if you happen to notice when your server will change it may help.
This is how you can tell when your DNS server will change.
1) Click Start.
2) Click Run.
3) Type "cmd" in the "Open" line.
4) Type "ipconfig /all"
5) Towards the bottom you should see a line called "DNS Servers". Below that it will say "Lease Obtained" and "Lease Expires".
It is the "Lease Expires" time that you want to be looking at. Let's say that your DNS server will expire in 2 days at 9:45 PM. What you would do is this: at 9:10 you would download something. Then your DNS server would automatically change, so at 9:46 you could download another movie.
I only recommend attempting this if you have very large movies that would be too big to download from megaupload/sexuploader etc.
Just thought I'd let you know!