I've just checked in a new package into the Zope 3 base subversion repository called Clarity. What it does is integrate ClearSilver templating into Zope 3 (trunk, though I expect Zope X3.0 or even Five support should be easy enough). It's all still rough, but initial tests show ClearSilver templates can be quite a bit faster than ZPT, and they have other possible benefits. In my simplistic experiments I got transaction rates about 2 to 5 times higher than you can reach with ZPT, testing this with the 'siege' utility.
Here's an extract from the README that describes the motivation for this experiment.
Zope 3 already has page template and even DTML, why would I want to use this? Some possible benefits ClearSilver brings are:
However, since no significant codebases exist that use this facility, these benefits are somewhat speculative.
More about ClearSilver here:
A comparison with other templating system and a motivation for its design, which they call dataset driven templates, can be found here.
Among other systems which use ClearSilver templates is Trac, the Python-based software project management tool:
You can check out Clarity from the Zope 3 base, here: