Version 2.2.0

You have to understand the version philosphy of Ubuntu and the relationship with Debian.
see https://wiki.ubuntu.com/UbuntuDevelopment
and https://wiki.ubuntu.com/UbuntuDevelopment/ReleaseProcess
and https://wiki.ubuntu.com/DebianImportFreeze

The current version of scons in Debian is as follows:
Package scons
squeeze (stable) (devel): replacement for make
 2.0.0-1: all
squeeze-backports (devel): replacement for make
 2.1.0-1~bpo60+1 [backports]: all
wheezy (testing) (devel): replacement for make
 2.1.0-1: all
sid (unstable) (devel): replacement for make
 2.1.0-1: all
experimental (rc-buggy) (devel): replacement for make
 2.2.0-1: all

When the 2.2.0 release will be taken over to testing and/or unstable in Debian, the next Ubuntu release will probably also include the upgraded version.
In case of important feature changes (e.g. security issues) also an release upgrade of a package in an existing Ubuntu release can be done, see https://wiki.ubuntu.com/StableReleaseUpdates

And of course you can always try compiling the package yourself or search for someone else who has done that in a ppa.

http://sourceforge.net/projects/scons/files/scons/2.2.0/

You can always grab the source and compile. You may get lucky with the noarch rpm and convert it to a deb using alien. Its not really advised in any way but can work. Your choice