Tasker
Powerful application that allows you to automate everything on your android device. Require root for usage.
Reddit Sync
Best Reddit application (imo), actively developed by Reddit user ljdawson
Really loving my Nexus 7 and it just keeps getting better with every new version of Paranoid Android
For those who don't know Paranoid Android is an ASOP based rom for many devices including the Nexus 7 that allows you to change the DPI and layout mode for individual apps as well as some cherry picked features from Cyanogen mod.