I get stuck in a pinch all the time without the tools I'm familiar with and have a few quick hack-arounds that I use now and then.
As far as SSH goes, you can manually invoke FTP from a command line to send a file to another server or use WGET to quickly grab a file.
One way to accomplish downloading from an SSH client is to make a gzip'd tar file of whatever you want to download. Move it to a public HTTP area and then download the file in your browser and delete it from the server afterwards.
Now, for something really cheesy:
You can edit text files locally and "upload" those text files in SSH by pasting them into a blank VI session and then saving the file.
Besides, you can FTP from any windows machine without downloading or installing anything.
Just drop into the Windows command line interface and when you get a C: prompt type in that magic word... FTP and hit return.
ftp> login example.com
User <example.com>: user name
ftp> ? (shows all commands)
Now you can view files, change directories, PUT or GET to upload/download then...
and you're done :)
Now to drift off topic about the FTP clients others discussed:
FWIW, I use a commercial FTP program because it uses multiple threads to upload and download so I can fully max out my cable modem and bring 100MB of database files from my server to my local machine in just a couple of minutes.
Likewise, I can upload hundreds of small files in very little time.
To put it bluntly, the cost of the software was completely justified for all the time I saved transferring files using older FTP clients.
Most stuff like this comes with a 30 day free eval so you can install it anywhere and use it for free in a pinch.
[edited by: incrediBILL at 9:39 pm (utc) on April 8, 2008]