A simple launcher
Kupfer is a summoner/launcher in the style of Quıcĸsılⅴεʀ or Gnome Do; you do not use it to search your files, you use it to summon the object you are thinking about right now.
Kupfer is written using Python and has a flexible architecture. Objects that it can access are implemented in plugins, and new plugins can be written quickly. (Tracker desktop search engine integration is only 130 lines.)
The philosophy of Kupfer is simplicity. The implementation is simple, makes the easy things work first, and does not overimplement unnecessary parts of the program. Kupfer is not as slick in its apprearance compared to its inspiration Quicksilver.
The installation is simple and uses waf; install Kupfer for your user just by
./waf configure --prefix=~/.local
Many Python modules are required, of course, gtk, gio, dbus and xdg, but others such as wnck are needed for specific plugins.
When you run kupfer, kupfer launches, run kupfer again -- and its window is presented immediately. There is no need to build global keyboard shortcut support into Kupfer -- just assign a global shortcut to kupfer using existing means, such as in metacity. I recommend using the shortcut < Ctrl >space but you can choose whatever suits your needs.