CMA Music Festival: Country's Night to Rock (8pm, ABC) - Pretty much every country music artist you can think of from A-to-Z (from Jason Aldean to the Zac Brown Band) gathers to get their rock on.
Greek (9pm, ABC Family) - In the third season opener of this smart, funny drama, Casey is dealing with Cappie's rejection and Cappie learns of Max's departure. Meanwhile, Rusty's grades begin to slip and he risks being dropped from the honors program.
9/11: Science and Conspiracy (9pm, NGC) - The National Geographic Channel probes common conspiracy theories about 9/11.
Hoarders (10pm, A&E) - It's the horror we can't look away from. Tonight a woman's sick husband is removed their home because of the filth and accumulated junk.
Weeds (10pm, Showtime) - The season finale has Nancy scrambling to secure herself and her future after learning of Esteban's fate, and Andy resolves to make some changes in his decidedly unfocused life. Also, Doug, Dean, and Celia come to an amicable agreement, and Silas decides he must help Adelita.