As you may know, FluxBox is a window manager, ideal for lightweight Linux systems, running on old computers. It is a good alternative for OpenBox, the default window manager for Crunchbang OS.
Because FluxBox is available in the default repositories on the most popular Linux systems, installing it is easy.
To Install FluxBox on Ubuntu 13.10 Saucy Salamander, Ubuntu 13.04 Raring Ringtail, Ubuntu 12.10 Quantal Quetzal, Ubuntu 12.04 Precise Pangolin, Ubuntu 10.04 Lucid Lynx, Linux Mint 16 Petra, Linux Mint 15 Olivia, Linux Mint 14 Nadia and Linux Mint 13 Maya, Debian Jessie, Debian Sid, Debian Wheezy and Debian Squeeze, just update the system and run the installation command:
$ sudo apt-get update
$ sudo apt-get install fluxbox