First see Install Libevent in Userspace.
$ cd ~/downloads $ tar xvfz tmux-1.4.tar.gz $ cd tmux-1.4 $ ./configure
$ export PATH=~/local/bin:$PATH $ export LD_LIBRARY_PATH=~/local/lib:$LD_LIBRARY_PATH $ LDFLAGS+=" -L/home/username/local/lib" \ CPPFLAGS+=" -I/home/username/local/include" \ PREFIX="/home/username/local" make $ LDFLAGS+=" -L/home/username/local/lib" \ CPPFLAGS+=" -I/home/username/local/include" \ PREFIX="/home/username/local" make install
Add
export PATH=$PATH:~/local/bin export LD_LIBRARY_PATH:~/local/lib
You now have tmux installed fully w/o the need for root.