Chemistry. It's a word tossed around in plenty of movie reviews, generally to diagnose whether two actors have it or not. Chemistry can be in the eye of the beholder: some critics may disagree, but if the chemistry is really there, it will show in the way the film catches on. No one can deny that Billy Crystal and Meg Ryan had it in When Harry Met Sally, or that William Powell and Myrna Loy, or Woody Allen and Diane Keaton had it in their many films. But for every hit, there are many, many failed experiments. Here are seven of the most (or least) memorable.

1. Fred Astaire and Joan Fontaine in A Damsel in Distress (1937)
For whatever reason, Astaire decided to break up his hit formula with Ginger Rogers and make this movie without her. His new partner? Joan Fontaine, best known for playing mousy, quietly pretty types (Rebecca, Letter from an Unknown Woman, etc.) and definitely not a song-and-dance woman. Poor Joan was taken to the mat for her lack of singing and hoofing, although the film actually isn't that bad. The ultra-witty P.G. Wodehouse adapted his own novel, it won an Oscar for its dance choreography, and it features another great team: George Burns and Gracie Allen.

2. Hugh Grant and Sandra Bullock in Two Weeks Notice (2002)
Every so often some Hollywood executive gets the idea to team up two big stars, hoping that their massive appeal will translate into screen chemistry; it mostly doesn't. These two romantic comedy masters, who have been wonderful in other films with other people, came together like a dull, wet flint, unable to strike even the most meager spark. Another infamous example of this type of casting came in 1986: recent Oscar winners Jack Nicholson and Meryl Streep came together for Mike Nichols' Heartburn. Before it opened, it had lots of buzz. After it opened, it had more of a stench.

Included in this week's new releases is Mr. Magorium's Wonder Emporium, a film I was sure would be retitled before being introduced to the public. Alas, it was not, and if it fails at the box office, there's a high likelihood that the title will be blamed. Of course, it isn't the worst movie title in history. The contenders for that honor are featured in a list over at MSN Movies, written up to "celebrate" this week's addition to the bad name hall of fame. The MSN writer vows never to see Magorium simply because he or she refuses to say the title out loud (you could see it without stating the name, if you buy your tickets online). Personally, I wouldn't mind asking for a ticket to the movie, but I'm apt to accidentally call it Food Emporium, since that's what always comes up in my mind when I'm thinking about the Dustin Hoffman/Natalie Portman Willy Wonka rip-off.

For some reason MSN's top ten worst film titles includes Octopussy, which I'm sure I'm not alone in thinking is in fact one of the BEST movie titles ever (and best title fonts ever). I also have a soft spot for titles Gigli, Operation Dumbo Drop and one of the runners-up, The Sisterhood of the Traveling Pants. I would probably substitute those with Ballistic Ecks vs. Sever, BlackMale, K-19 The Widowmaker and K-PAX (maybe I just hate K-titles, which now make me think of K-Fed), all of which were included in another bad-movie-title list on Retro Crush from 2003. No list is perfect, though, and for some reason Retro Crush actually hates on longtime favorite Breakin' 2: Electric Boogaloo (it's bad, but it's also so good!). Other nominees for the worst title of all time can be found at Wanderlist (perfect example: The Englishman Who Went Up a Hill But Came Down a Mountain) and Mutant Reviews (more hatin' on Breakin' 2? pffft!). So, what is your pick for worst movie title ever?

Chemistry -- you can be the best filmmaker, writer or actor, but nothing makes up for a lack of that intangible connection between two people. This is probably why so many actors can't keep up long relationships -- they continually get paired up with people they have great chemistry with and are weakened by temptation over and over until they can't help but break the ties that bind and go libidinously nuts. Oh, the devilish temptation! But on the flip-side, there are pairings that are just plain crappy -- painfully free of that interest and attraction that comes from the eyes. The CBC has reported that British cinema advertisers Pearl and Dean recently conducted a survey asking 3,000 movie-goers which duos have the worst on-screen chemistry, and came up with a list of the 10 worst offenders.

The top spots are no big surprise, really -- the 5th went to Catherine Zeta Jones and Sean Connery in Entrapment, the 4th to Madonna and Adriano Giannini in Swept Away, Keira Knightley and Orlando Bloom got the third spot with the Pirates of the Caribbean trilogy, the runners up were the rockin' Bennifer pair for Gigli and the top spot went to Natalie Portman and Hayden Christensen with Episode II: Attack of the Clones. I'd say they're pretty spot on, although my top offender are the two that hold that third spot, and I'm glad I'm not the only one that thinks so. Granted, Johnny Depp can whip up some chemistry with almost anyone, which makes it hard to compete, but man, I hated Knightley and Bloom together. This also made many parts of the final film truly annoying, if you get my drift. Also, you've got to question your real-life couple choices when you can't cook up chemistry at work, with your significant other.

Finishing the list, there's Hugh Grant and Andie MacDowell in the 6-spot with Four Weddings and a Funeral, Ben Affleck appeared again at 7 with Kate Beckinsale for Pearl Harbor, Tom Cruise and Nicole Kidman got 8 with Eyes Wide Shut, Heath Ledger and Jake Gyllenhaal followed with Brokeback Mountain and Titanic got the final, 10th spot, with stars Kate Winslet and Leonardo DiCaprio. Who would you pick?

The term "turkey" was long ago coined to describe either bad movies or huge financial flops, and there is a long list of them. (Although Kevin Costner movies like Waterworld or The Postman could better be described as "ham.") I combed through the trash to find seven treasures that I would actually recommend; these are the Butterballs.

1. Ishtar (1987, Elaine May)
Today, it's actually fairly difficult to see Ishtar, that "musical comedy" starring Dustin Hoffman and Warren Beatty, even if you wanted to. It hasn't yet been released on DVD (except in the UK), and I bet most of those old VHS tapes have been carefully disposed of. But Elaine May's famous flop deserves reconsideration, if only because recent years have shown that May's first three films, A New Leaf (1971), The Heartbreak Kid (1972) and Mikey and Nicky (1977), were masterworks way ahead of their time.