Node is currently one of those rare packages that are easier to build from source rather than from deb binaries.

apt-get update
apt-get install build-essential g++
cd /usr/local/src
tar xzf /tmp/node-v0.8.2.tar.gz
cd node-v0.8.2
./configure --without-ssl
make -j4
make install

will put node in /usr/local/{bin,lib,include,share/man}.

cd /tmp
tar xzf /tmp/cloudhead-less.js-v1.0-558-g5974b9e.tar.gz
mv /tmp/cloudhead-less.js-5974b9e /usr/local/lib/node_modules/lessjs
cd /usr/local/bin
ln -s ../lib/node_modules/lessjs/bin/lessc

will make the less compiler available in /usr/local/bin.

Now you can

lessc less/mybootstrap.less css/mybootstrap.css


lessc -x less/mybootstrap.less css/mybootstrap.min.css