Prerequisites

Please note, some of these packages may not be strictly required, but the lists should be sufficient.

sudo apt-get update
sudo apt-get install gcc libtool bison pkg-config gettext make bzip2 g++ wget

yum update -y
yum install -y make automake glibc-devel gcc-c++ gcc bison pkgconfig gettext-libs autoconf libtool wget

Installation

wget http://download.mono-project.com/sources/mono/mono-2.10.6.tar.bz2

tar xjf mono-2.10.6.tar.bz2
cd mono-2.10.6

./configure --prefix=/opt/mono/ --with-sgen=yes --with-gc=sgen

make

This part takes a while...

sudo make install

mono --version