diff --git a/lib/rbenv.zsh b/lib/rbenv.zsh
new file mode 100644
index 000000000..a8b6c323c
--- /dev/null
+++ b/lib/rbenv.zsh
@@ -0,0 +1,2 @@
+# using the rbenv plugin will override this with a real implementation
+function rbenv_prompt_info() {}
diff --git a/themes/crunch.zsh-theme b/themes/crunch.zsh-theme
index b2759a1b0..2fc066381 100644
--- a/themes/crunch.zsh-theme
+++ b/themes/crunch.zsh-theme
@@ -29,7 +29,7 @@ ZSH_THEME_GIT_PROMPT_DIRTY=" $CRUNCH_GIT_DIRTY_COLOR✗"
 
 # Our elements:
 CRUNCH_TIME_="$CRUNCH_BRACKET_COLOR{$CRUNCH_TIME_COLOR%T$CRUNCH_BRACKET_COLOR}%{$reset_color%}"
-if which rvm-prompt &> /dev/null; then
+if [ -e ~/.rvm/bin/rvm-prompt ]; then
   CRUNCH_RVM_="$CRUNCH_BRACKET_COLOR"["$CRUNCH_RVM_COLOR\${\$(~/.rvm/bin/rvm-prompt i v g)#ruby-}$CRUNCH_BRACKET_COLOR"]"%{$reset_color%}"
 else
   if which rbenv &> /dev/null; then
diff --git a/themes/dallas.zsh-theme b/themes/dallas.zsh-theme
index c9e335521..e9e86177b 100644
--- a/themes/dallas.zsh-theme
+++ b/themes/dallas.zsh-theme
@@ -3,7 +3,7 @@
 # Grab the current date (%D) and time (%T) wrapped in {}: {%D %T}
 DALLAS_CURRENT_TIME_="%{$fg[white]%}{%{$fg[yellow]%}%D %T%{$fg[white]%}}%{$reset_color%}"
 # Grab the current version of ruby in use (via RVM): [ruby-1.8.7]
-if which rvm-prompt &> /dev/null; then
+if [ -e ~/.rvm/bin/rvm-prompt ]; then
   DALLAS_CURRENT_RUBY_="%{$fg[white]%}[%{$fg[magenta]%}\$(~/.rvm/bin/rvm-prompt i v)%{$fg[white]%}]%{$reset_color%}"
 else
   if which rbenv &> /dev/null; then
diff --git a/themes/half-life.zsh-theme b/themes/half-life.zsh-theme
new file mode 100644
index 000000000..c8d09ce47
--- /dev/null
+++ b/themes/half-life.zsh-theme
@@ -0,0 +1,99 @@
+# prompt style and colors based on Steve Losh's Prose theme:
+# http://github.com/sjl/oh-my-zsh/blob/master/themes/prose.zsh-theme
+#
+# vcs_info modifications from Bart Trojanowski's zsh prompt:
+# http://www.jukie.net/bart/blog/pimping-out-zsh-prompt
+#
+# git untracked files modification from Brian Carper:
+# http://briancarper.net/blog/570/git-info-in-your-zsh-prompt
+
+function virtualenv_info {
+    [ $VIRTUAL_ENV ] && echo '('`basename $VIRTUAL_ENV`') '
+}
+PR_GIT_UPDATE=1
+
+setopt prompt_subst
+autoload colors
+colors
+
+autoload -U add-zsh-hook
+autoload -Uz vcs_info
+
+#use extended color pallete if available
+if [[ $TERM = *256color* || $TERM = *rxvt* ]]; then
+    turquoise="%F{81}"
+    orange="%F{166}"
+    purple="%F{135}"
+    hotpink="%F{161}"
+    limegreen="%F{118}"
+else
+    turquoise="$fg[cyan]"
+    orange="$fg[yellow]"
+    purple="$fg[magenta]"
+    hotpink="$fg[red]"
+    limegreen="$fg[green]"
+fi
+
+# enable VCS systems you use
+zstyle ':vcs_info:*' enable git svn
+
+# check-for-changes can be really slow.
+# you should disable it, if you work with large repositories
+zstyle ':vcs_info:*:prompt:*' check-for-changes true
+
+# set formats
+# %b - branchname
+# %u - unstagedstr (see below)
+# %c - stagedstr (see below)
+# %a - action (e.g. rebase-i)
+# %R - repository path
+# %S - path in the repository
+PR_RST="%{${reset_color}%}"
+FMT_BRANCH=" on %{$turquoise%}%b%u%c${PR_RST}"
+FMT_ACTION=" performing a %{$limegreen%}%a${PR_RST}"
+FMT_UNSTAGED="%{$orange%}●"
+FMT_STAGED="%{$limegreen%}●"
+
+zstyle ':vcs_info:*:prompt:*' unstagedstr   "${FMT_UNSTAGED}"
+zstyle ':vcs_info:*:prompt:*' stagedstr     "${FMT_STAGED}"
+zstyle ':vcs_info:*:prompt:*' actionformats "${FMT_BRANCH}${FMT_ACTION}"
+zstyle ':vcs_info:*:prompt:*' formats       "${FMT_BRANCH}"
+zstyle ':vcs_info:*:prompt:*' nvcsformats   ""
+
+
+function steeef_preexec {
+    case "$(history $HISTCMD)" in
+        *git*)
+            PR_GIT_UPDATE=1
+            ;;
+        *svn*)
+            PR_GIT_UPDATE=1
+            ;;
+    esac
+}
+add-zsh-hook preexec steeef_preexec
+
+function steeef_chpwd {
+    PR_GIT_UPDATE=1
+}
+add-zsh-hook chpwd steeef_chpwd
+
+function steeef_precmd {
+    if [[ -n "$PR_GIT_UPDATE" ]] ; then
+        # check for untracked files or updated submodules, since vcs_info doesn't
+        if [[ ! -z $(git ls-files --other --exclude-standard 2> /dev/null) ]]; then
+            PR_GIT_UPDATE=1
+            FMT_BRANCH="${PM_RST} on %{$turquoise%}%b%u%c%{$hotpink%}●${PR_RST}"
+        else
+            FMT_BRANCH="${PM_RST} on %{$turquoise%}%b%u%c${PR_RST}"
+        fi
+        zstyle ':vcs_info:*:prompt:*' formats       "${FMT_BRANCH}"
+
+        vcs_info 'prompt'
+        PR_GIT_UPDATE=
+    fi
+}
+add-zsh-hook precmd steeef_precmd
+
+PROMPT=$'
+%{$purple%}%n%{$reset_color%} in %{$limegreen%}%~%{$reset_color%}$(rvm-prompt " with%{$fg[red]%} " v g "%{$reset_color%}")$vcs_info_msg_0_%{$orange%} λ%{$reset_color%} '
diff --git a/themes/macovsky-ruby.zsh-theme b/themes/macovsky-ruby.zsh-theme
index 045376761..69d80d588 100644
--- a/themes/macovsky-ruby.zsh-theme
+++ b/themes/macovsky-ruby.zsh-theme
@@ -1,7 +1,7 @@
 # ZSH Theme - Preview: http://gyazo.com/8becc8a7ed5ab54a0262a470555c3eed.png
 local return_code="%(?..%{$fg[red]%}%? ↵%{$reset_color%})"
 
-if which rvm-prompt &> /dev/null; then
+if [ -e ~/.rvm/bin/rvm-prompt ]; then
   PROMPT='%{$fg[green]%}%~%{$reset_color%} %{$fg[red]%}‹$(~/.rvm/bin/rvm-prompt i v)› %{$reset_color%} $(git_prompt_info)%{$reset_color%}%B$%b '
 else
   if which rbenv &> /dev/null; then
diff --git a/themes/macovsky.zsh-theme b/themes/macovsky.zsh-theme
index b6978b929..2e6dce42d 100644
--- a/themes/macovsky.zsh-theme
+++ b/themes/macovsky.zsh-theme
@@ -1,7 +1,7 @@
 # ZSH Theme - Preview: http://gyazo.com/8becc8a7ed5ab54a0262a470555c3eed.png
 local return_code="%(?..%{$fg[red]%}%? ↵%{$reset_color%})"
 
-if which rvm-prompt &> /dev/null; then
+if [ -e ~/.rvm/bin/rvm-prompt ]; then
   PROMPT='%{$fg[green]%}%~%{$reset_color%} %{$fg[red]%}‹$(~/.rvm/bin/rvm-prompt i v)› %{$reset_color%} $(git_prompt_info)%{$reset_color%}%B$%b '
 else
   if which rbenv &> /dev/null; then
diff --git a/themes/superjarin.zsh-theme b/themes/superjarin.zsh-theme
index 0be816de0..86955a560 100644
--- a/themes/superjarin.zsh-theme
+++ b/themes/superjarin.zsh-theme
@@ -1,5 +1,5 @@
 # Grab the current version of ruby in use (via RVM): [ruby-1.8.7]
-if which rvm-prompt &> /dev/null; then
+if [ -e ~/.rvm/bin/rvm-prompt ]; then
   JARIN_CURRENT_RUBY_="%{$fg[white]%}[%{$fg[red]%}\$(~/.rvm/bin/rvm-prompt i v)%{$fg[white]%}]%{$reset_color%}"
 else
   if which rbenv &> /dev/null; then
diff --git a/themes/zhann.zsh-theme b/themes/zhann.zsh-theme
index 574e0cec3..5c49fe79b 100644
--- a/themes/zhann.zsh-theme
+++ b/themes/zhann.zsh-theme
@@ -1,6 +1,6 @@
 PROMPT='%{$fg_bold[green]%}%p %{$fg[cyan]%}%c%{$fg_bold[blue]%}$(git_prompt_info)%{$fg_bold[blue]%} % %{$reset_color%}'
 
-if which rvm-prompt &> /dev/null; then
+if [ -e ~/.rvm/bin/rvm-prompt ]; then
   RPROMPT='%{$reset_color%} %{$fg[red]%}$(~/.rvm/bin/rvm-prompt i v g) %{$reset_color%}'
 else
   if which rbenv &> /dev/null; then