The Ellen DeGeneres Show
(3 p.m., NBC10) - Helen Mirren; Katy Perry performs.
MythBusters (9 p.m., DISC) - Adam and Jamie tackle a request from President Obama: to retest the myth of the Archimedes Solar Ray, using mirrors as a weapon.
The Defenders (10 p.m., CBS3) - Nick and Pete try to help a young man arrested for carrying guns with filed-off serial numbers.
Tyler Perry's Meet the Browns (10 p.m., TBS) - Brianna uses her design skills to make over a homely girl.
The Daily Show With Jon Stewart (11 p.m., COM) - Michelle Williams.
Conan (11 p.m., TBS) - Ray Romano; Arianna Huffington; LXD performs.
The Colbert Report (11:31 p.m., COM) - Steve Martin.
Late Show With David Letterman (11:35 p.m., CBS3) - Barbara Walters; Alison Balsom performs.
The Tonight Show With Jay Leno (11:35 p.m., NBC10) - Jeff Bridges.
Lopez Tonight (midnight, TBS) - Alan Cumming.
Jimmy Kimmel Live (12:06 a.m., 6ABC) - Helen Mirren; Paul Bettany; Little Big Town.
The Late Late Show With Craig Ferguson (12:37 a.m., CBS3) - Russell Brand.
Late Night With Jimmy Fallon (12:37 a.m., NBC10) - Ben Affleck.