We're approaching the halfway point of the 2012 Democratic National Convention, and tonight's speaker list has a little bit for everyone: a former president, a gay congressman, a 2016 hopeful, a potential Supreme Court justice and a liberal icon.

Below, we take a look at the five speakers who demand the attention of any self-respecting political junkie:

* Rep. Barney Frank (8 p.m. hour): Gay rights have been a significant and novel theme of the convention so far, and several gay speakers have already taken to the stage. But nobody will drive home the Democrats' embrace of gay marriage like Frank, the longtime former Financial Services Committee chairman who recently became the first member of Congress to marry his same-sex partner. Frank is also retiring from Congress this year, meaning this could amount to the curtain call in a long and colorful career.

* John Hickenlooper (8 p.m. hour): Of all tonight's speakers, the Colorado governor is the most likely potential 2016 Democratic presidential candidate. And tonight's speech will be the first taste that many will get of Hickenlooper. The former Denver mayor is extraordinarily popular in his home state, but can he make the leap to national relevance? Tonight will say a lot about that. Hickenlooper can also be an extremely valuable surrogate for Obama in a key state.

* Kamala Harris (9 p.m. hour): Relatively few watching tonight will have heard of Harris. But that should change shortly. The new California attorney general is a rising star in her party and many see her as the next governor of that state -- or even a Supreme Court justice. In fact, the ever-great SCOTUSblog sees her as the ideal nominee for the next Court vacancy (if Obama is still president, of course). She's relatively young (47), attractive, female, and has both African-American and Indian-American heritage. And California is obviously a very important state for Democrats.

* Elizabeth Warren (10 p.m. hour): As The Fix's Sean Sullivan wrote today, Warren has a lot at stake in her speech tonight. She began with high hopes as the Democrats' challenger to Sen. Scott Brown (R-Mass.) and a liberal favorite, but she's at risk of falling behind Brown in the polls right now. It will be interesting to see whether she doubles down on the kind of rhetoric that has endeared her to the left or goes for a more middle-of-the-road message. Right now, independents are going overwhelmingly for Brown.

* Bill Clinton (10 p.m. hour): Who else? Clinton still commands the attention of Americans -- and the media -- like no other political figure, and his popularity is basically as high as it ever was during his presidency. Democrats see Clinton tying himself to Obama as a potential game-changer, but Clinton has also said some things that haven't been entirely helpful to the current president's reelection campaign. And there are lingering doubts that Clinton has much regard for the man he will promote tonight. But if Clinton is on his game and can press the case that Obama is continuing Clinton-era policies, it could be big for Democrats. (More on Clinton's speech from Papa Fix is here.)

Watch LIVE video of these speakers on The Grid.