We need a bit more information here. How long have you had the cat? Has there been a recent change in your household routine? Do you have a regular play time?
Sam cries like that when he wants something; yesterday he cried for 2 hours until I took him outside for a few mintues, then he was quiet. Its usually to tell you something....you just have to figure out what it is they are saying.
No there's been no change in the routine here, and we don't have a regular playtime, but I play with her from time to time throughout the day. I really think the cry is to go outside, but I want her to be an indoor cat (although I'm tempted to let her go out when she does that crying). I don't want to start with fleas and ticks, much less take a chance that she would get into trouble and need a vet, or worse.
Like Zoey, Max meows to get my attention. He will go in the other room and let a string of the most pitiful meows and then I will say, "What's wrong my baby?" and he'll come running and we cuddle. It's like he's saying, "You need to pay more attention to me."