Language Specific
======================
PyCon https://us.pycon.org/2013/registration/
$600 + $150/training
March 13-17th
Big Data
=======================
Hadoop Summit
http://hadoopsummit.org/amsterdam/register/
~ $1750
March 20-21st
Game Dev
========================
Game Developers Conf
http://www.gdconf.com/
$?
March 25-29th
Hosting
HostingCon
http://www.hostingcon.com/
$399-$599 (depends on when you register)
June 17-19
Web Performance
Velocity
http://velocityconf.com/velocity2013/
June 18-20th
Open Source
OSCON
http://www.oscon.com/oscon2013
July 22 - 26th
Startup
Microconf
http://www.microconf.com/
Date: Unknown
Other
CES
http://www.cesweb.org/Conference-Program/Conference-Pricing....
$1300
Jan 8-11th