2. He made Las Vegas a convention destination. When Adelson brought COMDEX to Vegas, the gambling mecca was generally hostile to the convention business, but Adelson had a vision of conventioneers filling hotel rooms and spending disposable income on the casino floor. To house COMDEX, he purchased the Sands Hotel -- the decrepit former home of the Rat Pack -- and built a massive convention center next to it, then aggressively marketed it as a destination for other conventions. Today, the convention business is a cornerstone of the Las Vegas economy. Adelson expanded his empire with two high-end hotel-casino-resorts, the Venetian (1999) -- complete with gondoliers ferrying tourists down fake canals -- and the Palazzo, which opened in 2007.

3. He's a union-buster. Some of Adelson's bitterest political battles have been fought in his adopted home state against the forces of organized labor, which has a strong foothold in the casino industry. The Venetian opened in 1999 as the only non-union casino on the Strip and has been the target of protest from the hotel workers union, Culinary 226, ever since. Many Democratic politicians in the state continue to observe the union's boycott of Adelson's properties. Rep. Shelley Berkley, a Nevada Democrat now running for Senate in what's likely to be one of 2012's highest-profile races, was once Adelson's top political lieutenant, but the two parted ways over labor issues. Adelson and Berkley have regarded each other as mortal enemies ever since -- even though Berkley, like Adelson, is a hawkish, socially liberal Jew.

4. He spent $30 million on the 2008 election. It didn't work out so well. Adelson poured the money into Freedom's Watch, a "527" independent-expenditure group that was active in congressional races, airing ads across the country that emphasized national security. (It also ran ads targeting Berkley, though her safe Democratic seat was not remotely competitive.) The group's help failed to avert the Republican landslide that November, and it was further hampered by staff infighting; insiders accused Adelson, its nearly sole donor, of micromanaging the organization's activities. It closed shortly after the 2008 general election. Notably, a top official at Freedom's Watch, Carl Forti, is now a chief strategist for Restore Our Future, Mitt Romney's super PAC -- putting him in direct opposition to Adelson's pro-Gingrich super-PAC.

5. He's a Zionist/neocon/right-wing Israel hawk. Much of Adelson's political activity is devoted to boosting the right-wing Israeli line, both in Israel and the U.S. He donated a posh new headquarters to AIPAC, the Israel lobby in Washington, though he reportedly feuded with the organization over activities he saw as unduly pro-Palestinian. He has given $25 million to Yad Vashem, the Israeli Holocaust memorial organization, and $100 million to Birthright, the organization that takes young American Jews on free trips to Israel to bolster their loyalty to the Jewish state. Adelson opposes a two-state solution or any accommodation of Palestinians. When Gingrich recently stirred controversy by referring to the Palestinians as "an invented people," Adelson praised the remark to a Birthright group, according to the Israeli newspaper Haaretz. In Israel, Adelson started a free daily newspaper known for its relentless drumbeat of support for Prime Minister Benjamin Netanyahu and other right-wing politicians. The paper, Israel Hayom, has been called "the Fox News of Israel." Adelson's millions of dollars in contributions have purchased access to the highest reaches of the GOP -- during the Bush administration, for example, he hosted both President Bush and Vice President Cheney in his home -- and he has used it principally to push for a hard line on Israel.