If you like that you'll love this.

Ubuntu is a bit of a bugger for not updating BOINC in the repositories but since it sprays the BOINC files around like hippo manure in the file system it can be a little daunting for a new guy wanting to update the client. Here's the skinny.

Open a terminal (via ssh/Putty or locally) and enter:
Code:
sudo /etc/init.d/boinc-client stop
to stop the client and
Code:
wget http://boinc.berkeley.edu/dl/boinc_6.12.34_x86_64-pc-linux-gnu.sh
replace the version numbers with whatever version you're after. If you're not sure go here and look: http://boinc.berkeley.edu/dl
This will download the file directly from Berkley to the current directory, which should be your home directory.
Next set the file as executable
Code:
sudo chmod +x boinc_6.12.34_x86_64-pc-linux-gnu.sh
and then run it
Code:
./boinc_6.12.34_x86_64-pc-linux-gnu.sh
That will create a directory called BOINC in your home folder. Change into it.
Code:
cd BOINC
now we'll copy the relevant binaries
Code:
sudo cp boinc* /usr/bin/
and we restart the client
Code:
sudo /etc/init.d/boinc-client start
That should be it. You're now running the new client version. Since Ubuntu pretty much never update it you don't have to worry about it being overwritten, but if it is just do the same thing again to change it back or update to another newer version, or back to an older one if there's a problem.