Coverage of the Republican National Convention (6 p.m., CNN, Current; 7 p.m., PBS, Fox News, MSNBC; 8 p.m., Bloomberg; and 9 p.m., ABC, CBS and NBC) airs tonight. The networks join the fray, as does “The Daily Show With Jon Stewart” (10 p.m., Comedy Central). Continuous live feeds of the gathering can be found on Internet sites maintained by YouTube (youtube.com/politics?featureinp-bp-ype-01) and C-SPAN (c-span.org/RNC).

A notable keynote address by Barack Obama in 2004 put him on the road to the White House. Bill Clinton delivered a long and rambling address at the 1988 convention and received applause only when he uttered the words, “in conclusion.” But his good humor in acknowledging this disaster (on “The Tonight Show” with Johnny Carson and elsewhere) helped put him on the national stage.

Tonight’s convention speakers also include former Pennsylvania Sen. Rick Santorum, who was bested in the Republican primaries by presumptive nominee Mitt Romney. There’s a tradition of having vanquished rivals join the proceedings in a gesture of party unity. It doesn’t always work out that way. At the Republican convention in 1964, liberal New York Gov. Nelson Rockefeller was greeted by jeers from conservative supporters of nominee Arizona Sen. Barry Goldwater.

Not all convention speeches are so memorable. Do you recall who delivered the keynote addresses for their respective parties in 2008? It was Republican Rudy Giuliani and Democrat Mark Warner. I’ll admit I had to look it up.

Tonight’s other highlights

• A dozen semifinalists perform on “America’s Got Talent” (7 p.m., NBC).

• On two episodes of “MasterChef” (Fox): fit for a president’s plate (7 p.m.), Michelin stars (8 p.m.).

• A defendant takes desperate measures to end his trial on “White Collar” (8 p.m., USA).

• Simon invites Annie to Cuba on “Covert Affairs” (9 p.m., USA).

• The guys renovate the town’s train station with the help of some unlikely visitors on “The Week the Women Went” (9 p.m., Lifetime).

• Gary gets custody on the season finale of “Teen Mom” (9 p.m., MTV).

• Roster cuts loom large on “Hard Knocks: Training Camp With the Miami Dolphins” (9 p.m., HBO).