I ran across a odd bug the other day. Essentially, when M-q is run with an open bracket in python mode, emacs will freeze. 

To replicate the error:

$ emacs test.py

type:

def test(

then hit M-q

The version of emacs I'm using is: 

GNU Emacs 24.3.1 (x86_64-pc-linux-gnu, GTK+ Version 3.10.7)

 of 2014-03-07 on lamiak, modified by Debian

Its not a huge deal, it just struck me as odd since it generally really difficult to get emacs to crash. 

Thanks,

Gaetan