Houston PBS affiliate KUHT-8 had last week's first round, and the six Texas Supreme Court justices and challengers all debated last Sunday evening in a joint appearance at South Texas College of Law, and tonight features the last of the two debates between the contestants for the United States Senate (apparently Yvonne Schick, the Libertarian, isn't going to be included in this one).
Here are the Texas PBS affiliates broadcasting it (it will also be live on C-SPAN 2):
Amarillo   KACV-TV (PBS) - Channel 2
(delayed - will air at 9 p.m.)   
Houston  KUHT-TV (PBS) - Channel 8
KRIV-TV (FOX) - Channel 26 (delayed - will air at 10:30 p.m.)
Austin  KLRU-TV (PBS) - Channel 18   
Killeen  KNCT-TV (PBS) - Channel 46
(delayed - will air at 9 p.m.)
Beaumont  KBMT-TV (ABC) - Channel 12
(delayed - will air at 10:30 p.m.)   
Lubbock  KTXT-TV (PBS) - Channel 5
KJTV-CA (FOX) - Channel 32
College Station  KAMU-TV (PBS) - Channel 15
Lufkin/Nacogdoches  KTRE-TV (ABC) - Channel 9
(delayed - will air at 11:05 p.m.)
Corpus Christi
KEDT-TV (PBS) - Channel 16
KDF-TV (Ind.) - Channel 47
Odessa  KPBT-TV (PBS) - Channel 36
Dallas/Fort Worth  KERA-TV (PBS) - Channel 13
KUVN-TV (Univisión) - Channel 23 - en Español (delayed - will air Sat, Oct. 18 at 10 a.m.)   
San Antonio KLRN-TV (PBS) - Channel 9
Tyler/Longview/Jacksonville  KLTV-TV (ABC) - Channel 7 (delayed - will air at 11:05 p.m.)
El Paso  KCOS-TV (PBS) - Channel 13 (will air live at 7 p.m. MT)
Waco  KWBU-TV (PBS) - Channel 34
Harlingen/Weslaco/Brownsville/McAllen
KMBH-TV (PBS) - Channel 60
KGBT-TV (CBS) - Channel 4
(delayed - will air at 12:30 a.m.)
Wichita Falls  KSWO-DT (ABC) - Channel 11.3
(will air live, with replay on Fri., Oct. 17 at 7 p.m.)
       
Central Texas
(Austin, Fredericksburg, Killeen, Temple, Waco) Time Warner Cable News 8 (will air live; replays on 10/16 at 10:30 p.m. and 10/17 at noon; also available on News 8; On Demand - TWC Channel 1408)
And if you can only catch it on the radio there are listings at the link.