Here's a neat trick: Measuring your Internet download speed from the command line.
Basically you need wget to download a big file (download to /dev/null will not waste disk space ;)) and simply check the average speed at the end.
Here's how to change a file's modified date:
touch -mt 201102260000 <file>
Where "201102260000" is year, month, day, hours, minutes all glued together (so 2011-02-26 at 00:00).
Also, if you want to change both the modified and creation...