IronPython 2.0 and Jython 2.5 performance compared to Python 2.5 - word of warning: both Jython and IronPython are significantly (and I mean significantly significantly) slower than CPython. The overhead for Jython with very large data structures is eventually better than with CPython, but for normal use it doesn't look so great.
Archive 22. February 2010
IronPython hammers CPython when not mutating class attributes - more information about the performance issue. Here related to IronPython - apparently class variables can be problematic in some cases, as the classes themselves change through them and thus JIT compiler information must be discarded (due to the rather static structure of the VM, both in the JVM and in the CLI, probably a very similar problem), which means the JIT compiler then has to rework everything and thus not only are performance advantages lost, but they can potentially even be counterproductive.
Polyglot - a really nice plugin for Chrome that translates random words into a configurable target language. Why? So that you can see new vocabulary from time to time while browsing and thus learn new vocabulary easily. I'm currently trying it with Russian and it's really a nice method - with the few words you have enough context of the sentence to deduce the word. This of course does not practice grammar or declensions and conjugations, but as a little vocabulary boost from time to time very useful.