Matt Parnell has an interesting method of speeding up his apt-get downloads by utilising the axel downloader.
A shell script appropriately called apt-fast is available from the link above.
Here is what Matt has to say about the project:
The apt-fast script I have created is a little shellscript that increases the speed of apt-get by many times. You need to have the axel download accelerator installed, which is a simple, short process, but everything else is extremely straight forward. I started out downloading the upgrades for Kubuntu, at 32kb/s. Not terrible, but not that great. When I was done with the script here, I was getting up to ~850kb/s. That is great, huh?
To do this, you first need to download and install the axel download accelerator. It is really a good drop-in replacement for wget, as it is bash based. Once installed, we are ready to setup apt-fast. On K/Ubuntu apt-get install axel should do it.
Then, either find a package somewhere (or install it from a repo if one of them has it), or just download the latest apt-fast source from the link mentioned at the top of this post. Then, just place the script somewhere (/usr/bin or /usr/sbin is ideal), rename it to apt-fast (without the .sh extension), and sudo chmod +x apt-fast.
Once done, just use it like apt-get. To install a single package, make sure your database is up to date (apt-fast update), and run apt-fast install packagenamehere. Watch it download with incredible speed, and install your requested packages. To upgrade or dist-upgrade, do the same thing. Just use apt-fast dist-upgrade or apt-fast upgrade. That’s all there is to it!
Should your download stall for any number of reasons, you’ll need to do an apt-fast clean.