Currently the April 2014 CU for SharePoint 2013 is NOT AVAILABLE/RELEASED yet.
Only a few single fixes are already available and can be installed separately.
So if you don’t have an urgent demand or need to install one of the listed fixes as a single one, please stay tuned and await the next full cumulative package in future.
Due to a recent discovered problem with the SP1 the April 2014 CU anyway might not properly install.
Before questions may come up, please read at first these posts below with some more information all about and what's up with the SP1 and/or April 2014 CU yet
Office Client packs are not affected, find them here:
As soon as any news are available, I’ll post it